Also known as:
Place of Origin:
Sasaki Kojirou (佐々木 小次郎, Sasaki Kojirō?), Class Name Assassin (アサシン, Asashin?), is the Assassin-class Servant of Caster in the Fifth Holy Grail War of Fate/stay night. He is an irregular Servant that shouldn't exist according to the rules of the Holy Grail War, but Caster's unique nature as a Servant summoning a Servant twists the process. The true Servant, one of the Hassan-i-Sabbah, is summoned as True Assassin in the Heaven's Feel route.
He is one of the Servants summoned by Ritsuka Fujimaru in the Grand Orders conflicts of Fate/Grand Order, appearing as both his Assassin-class self and as a Saber-class Servant, Nameless Saber (セイバー・無銘, Seibā Mumei?), during his duel with Miyamoto Musashi.
- 1 Profile
- 2 Role
- 2.1 Fate/stay night
- 2.2 Fate/hollow ataraxia
- 2.3 Fate/Unlimited Codes
- 2.4 Fate/tiger colosseum series
- 2.5 Fate/Grand Order
- 2.6 Carnival Phantasm
- 2.7 Today's Menu for Emiya Family
- 2.8 Fate/Requiem
- 2.9 Other appearances
- 3 Abilities
- 4 Forms and Alternate Versions
- 5 Development
- 6 References
A mythical Japanese swordsman said to have faced Miyamoto Musashi in combat. In reality, the individual summoned as Assassin's true name was unknown, and to be more specific, he never had a true name. Kojirou is known as a master swordsman whose existence is doubted even though his name remains recorded in history. He did not actually exist, so it would be impossible to summon the real thing as a Servant. The person summoned in his place is not a Heroic Spirit, but an existence closer to that of wraiths. If there was to be a database for all of humanity, he is the piece of data that best matches the parameters of Sasaki, so his personality would become Kojirou's personality and his monumental feats would become that of Kojirou rather than his own.
This individual was the son of an ordinary farming family, living an ordinary farm life and separated from ordinary common sense. He met a master swordsman who had retired deep into the mountains, and began his ordinary life in the mountains himself. He was enthralled by the swordsmanship of the master, and he began training under him the next day. The master swordsman only taught him the refined behaviour of a swordsman; a communion with nature and the master swordsman did not instruct him on anything related to sword techniques. After one month, the master swordsman drew his last breath, and he completely threw himself into the path of a swordsman. He was a nameless martial artist with some relation to the Ryuudou Temple, but there is no way to know his true identity. He died lacking a name, never even fortunate enough to be given one, and the ability to read or write. He utilizes a long Japanese katana and discovered the ultimate technique, “Tsubame Gaeshi”, being absolutely all he possesses. The reason he is summoned is simply because he can execute that legendary technique. He spent much of his life simply trying to figure out the best method to cut down a swallow, and although he realized the method was impossible for a human, he had nothing else to do and kept on practicing. While determination is normally the key to success, he simply noticed that it had succeeded.
The legendary Kojirou is known as cool and elegant, so Assassin's pursuit of sword technique, sophistication, and finding joy in dueling with strong foes is reminiscent of that character. Differing from the legend, his nodachi is longer, 1.5 meters compared to 90 centimeters and engraved with Bitchu Aoe (備中青江, Bichū Aoe?, Blue River of Bitchu). The Bitchu Aoe may have been the master's, or perhaps he received it from the Holy Grail when the legendary soul was summoned. It is simply something thought to be part of who he is. With any great deed performed by Assassin, the reward will go to "Sasaki Kojirou", as he is nothing and all his actions are meaningless. He is a disposable swordsman meant only to act out the role of Sasaki Kojirou, a fictional swordsman created from a fictional story.
While the Kojirou in the modern era is an invention, a blend of details from the lives of many nameless and forgotten historical swordsmen, he is said to have been born in the Eiroku era in the Echizen countryside according to records. His real name was speculated to be Tsuda (津田?). He studied under the originator of the Chujoryu kodachi style, Toda Seigen, favoring a long sword. He defeated the master's younger brother, and named his own style "Ganryu." He was known as a handsome swordsman wielding the 3-shaku-long, approximately 90 centimeters to one meter, nodachi, “Bizen Osahune Nagamitsu”, that was also called the “Monohoshi Zao". He traveled around the country as a master swordsman, and it is said that he developed his secret sword technique, Tsubame Gaeshi, able to kill even a flying swallow, around the Nishiki River in the Suou region.
He terrified swordsmen around the country after that period, and eventually battled Miyamoto Musashi at Funajima Island to maintain the reputation of the domain he served, dying in the process. He was unable to fight while holding onto the sheath of his sword due to its length, so he threw it away in front of Musashi. Musashi is quoted to have said the famous lines "Kojirou, you lose. If you are were planning to win, why did you throw away your sheath?" and “Kojirou has been defeated!" after seeing that event. The finale was of the battle was Kojirou's death after having either his forehead or chest crushed by an oar.
Musashi was one of Japan's best swordsmen, and Kojirou is known as Musashi's worthy rival. It is claimed that he gained fame around the period from the 10th to 17th year of the Keichou era, but his real figure is hazy like the moon on water. Any truth of this era is a mystery due to all books noting him being inconsistent in terms of years. His duel is legendary, and although he was said to be the disciple of Seigen, there are numerous conflicting documentations and legends, which still shroud his true identity even now. The only one who should know of the existence of such a swordsman would have to be the supposed rival who defeated him, Musashi, but he is not mentioned at all in the book Musashi wrote, "Gorin no Sho."
Kojirou was a Japanese man without any real identity, his birth is unknown, and his story was only told through word of mouth. His past was falsely forged as a convenient foe to a famed swordsman. The records are too vague, but it was likely there existed man named Sasaki Kojirou and a man who wielded a sword called the Monohoshi Zao. They would not have been the same person, so the swordsman with the name Sasaki Kojirou was simply a fictional character created to be his enemy's foil. Even if there was a person like him, it can be said that his figure passed down to the present is a fictional swordsman nor an overstatement to say that he has never existed.
Assassin's appearance is that of a samurai swordsman with long indigo hair tied into ponytail and indigo eyes. He wears a traditional light purple umanori hakama and kimono, light purple tabi and black zori with purple haori and tekkou and carries his sword, Monohoshi Zao on his back.
Assassin is quiet and composed, and while his general tone has a mocking nature to it, he takes it to another level with Caster. He is honorable in battle, always maintaining a degree of bushido, and he is not the type who would attack defenseless women and children. He willingly keeps Saber from exposing her name without any ulterior motives, and he prematurely stops their fight to keep an opponent from spying on her Noble Phantasm and possibly going after the weakened winner of the battle. He has no actual goal in participating in the Holy Grail War. He is not a Heroic Spirit, so there is no advantage to winning for him. He reveals his "true name" without regard, and seems disinterested in Caster's promised reward of making him into a real Sasaki. He only guards the gate while eagerly awaiting Servants to battle.
A refined man who admires the beauties of nature and wraps his body in an elegant battle surcoat. Aloof from the world and having a somewhat elusive personality but, as expected, he is a warrior who likes fair and square contests. Due to living in an age where casualties happened on a daily basis, his perspectives about life and death may also seem cold-hearted for a modern person.
- He greatly dislikes Caster, seeking to kill her if possible. Not wishing to be ordered around by a woman, her first Command Spell was to force him into obedience. During Fate/hollow ataraxia, he is very carefree and casual with her, freely insulting her and mocking her orders as he wishes. She attempts to have him do menial work, but he uses logic like that it would take more magical energy to take form to sweep than if she herself were to do it. True to her nature as a magus, the logic is impenetrable because she would never utilize magical energy frivolously. He mentions that he enjoys watching her interactions with Kuzuki due to him not giving her any recognition. It was one of his few sources of amusement, but eventually began to tire of it.
- Miyamoto Musashi
- Yukika Saegusa
- He befriends Yukika Saegusa, taking to her innocence that is like that of a puppy. He does his best to avoid the topic of his strange clothing and nature as a Servant.
Caster, borrowing the power of the Greater Grail, was able to obtain fake Command Spells and summon a fake Servant, Assassin. Assassin was summoned as a guardian and watchman for the front gate of Ryuudou Temple. As an improper Servant, Assassin is entirely dependent on Caster for mana and cannot move freely beyond the grounds of Ryuudou Temple. Furthermore, he lacks most of the usual parameters and abilities granted to his class. Because of his limited status, Assassin cares little for the Holy Grail, and outside of his duties to Caster, he only seeks to enjoy a decent sword duel.
In the Fate scenario, Assassin drives back Saber during her first assault on Ryuudou Temple. He is never seen after his initial confrontation with Saber. He is defeated at some point in the story but it is only mentioned and not shown, leaving the identity of his killer unknown.
In Fate/hollow ataraxia, it is revealed that Gilgamesh was the one who attacked Ryuudou Temple and killed both Assassin and Kuzuki.
In the 2006 anime, during their second meeting in Caster's underground temple, he allows Emiya Shirou and Tohsaka Rin to pass in order to engage Saber in a duel in which he is defeated.
Unlimited Blade Works
In the Unlimited Blade Works scenario, Assassin permits Archer entry into Ryuudou Temple so he can give that "vixen a scare." He then battles Saber, who notes the clear difference in their sword technique and survives Assassin's Tsubame Gaeshi. After Archer nearly kills Shirou, however, Assassin allows Saber to run to him, stating that her concern for her Master is admirable. He then protects Saber and Shirou from Archer and engages in combat with him. The winner is not shown, as Saber and Shirou flee while they have the chance.
After Caster uses Rule Breaker to steal Shirou’s Command Seals (and thus, Saber herself), she goes to inform Assassin she is heading to Kotomine’s Church. He lets her know that he struck down a bird Familiar made of jewels belonging to Rin, and questions whether Kuzuki will approve of her actions done without his knowledge or consent. As punishment, she uses magic to rip his chest open. Despite his pain, he is not quite cowed, but nonetheless promises to guard the temple as ever, watching as his master departs with laughter.
On the last night of the Holy Grail War, Saber goes to the front gate of Ryuudou Temple to fight against Gilgamesh. However, Assassin still exists and wants to duel against Saber. He is defeated by Saber due to his blade being bent from their previous encounter, which leaves an opening in his Tsubame Gaeshi. Soon after, he dies peacefully.
In Fate/stay night - Heaven's Feel I. presage flower, he ends up being the first Servant to be absorbed by the Shadow after the birth of True Assassin, causing the interference that ends up making the Shadow in the Second Lesser Grail instead of Illya.
In Fate/hollow ataraxia, Assassin remains bound to Ryuudou Temple, and continues to watch over its front gate even though peace has settled over Fuyuki City. He converses with whoever is kind enough to climb up the steps to see him. Incidentally, he takes upon the pseudonym Kojirou Tsuda (津田小次郎, Tsuda Kojirō?).
When Avenger makes his move, Assassin fights the dog-shadows right beside his Master, Caster and Souichirou Kuzuki.
In Fate/Unlimited Codes, he is known as Nameless Samurai (無名の侍士, Mumei no Samuraishi?). Assassin's story follow as he was summoned by Caster, he notices that the environment to be familiar to Ryuudou Temple. Caster corrects Assassin that it has been many years since he last saw Ryuudou Temple and calls him as Sasaki Kojirou. While Assassin seems confused with his name, Caster claims it is a name that people of the modern age calls him. Caster explains to Assassin that she summoned him to serve her and refers him as Assassin. Caster orders Assassin to guard the mountain gate whether they are Magus or Servants, however Assassin refuse to take order from Caster. He claims that he has no problem offering his life to a cause but drawing his sword on a command of a woman doesn't suit him. Caster forces Assassin to submit to her orders when she used her Command Spells. Although Assassin follows her command, Assassin mocks Caster whether she can still control him by the end of the Holy Grail War.
His clash with Saber is interrupted when Assassin says that a third party member is observing their fight and the possibility of them to attack when they witness their secret technique or taking advantage on the injured winner. Assassin suggested Saber to retreat as he already figured out Saber's techniques and along with the possibility that the third party member will attack Shirou Emiya who is on his way to collect Saber. Caster appears and orders Assassin to finish Saber as she is both tired and exhausted. Assassin tells Caster not to interfere and told her he has no desire to settle things in a vulgar manner. Caster used her second command spell, she orders Assassin to finish off Shirou while Caster has an interest in Saber. As he wins, he feels Saber shame in surviving the duel and wonders what to do with Caster who has gone too far to interfere.
His final opponent is Berserker who has passed through the mountain gates and in to the inner grounds of the temple, Assassin can sense Berserker immense vigor. Berserker strikes Assassin with one blow, Caster in disbelief was convinced that Assassin had no chance in defeating Berserker. Caster used her final command spell to fight Berserker to the very end, Assassin used this opportunity to cut down Caster. He planned to have the final command spell to be used and in doing so, his reserved energy was activated. It appears that he has many energy left due to defeating his enemies without a single loss.
Shortly after Caster death, Assassin will be gone shortly but he is glad to have a worthy opponent in his final moments. Although he doesn't know Berserker identity but he knows he is an exceptional warrior and that he has to use his full force to win. After his victory, he never believed that he would face against a tough opponent and was satisfied with his time spent in the Holy Grail War. He compliments the beauty of the Moon and fades away.
|Fate/unlimited codes - Assassin command list|
Fate/tiger colosseum series
Do Moon Goddesses Dream of Dango?
Travelling with Martha and Georgios, Sasaki Kojirou runs into Marie Antoinette, Chevalier d’Eon, and Charles-Henri Sanson, who give them most of their dumplings as a sign of friendship. Afterwards, he and the others go to the waters of Marseille with him tagging along, hoping he’ll get to fight with Martha.
Later, Sasaki eats the dumplings with Georgios and Martha while they camp out near the shorelines Marseille. Martha asks him his reasons for tagging with her and Georgios. Sasaki answers as he did before, but Martha rejects his request to fight. Sasaki then wonders about Tarasque, and becomes intrigued by Martha’s fighting style when she states that neither his sword nor her punches can penetrate Tarasque’s scales. Ritsuka’s party soon arrives, with Mash demanding that they surrender their dumplings. Sasaki and others seemingly hand over their dumplings, but Artemis reveals that they’re still hiding some. Sasaki himself is hiding a rare dumpling in his pocket. With their poor deception unveiled by Artemis, Sasaki fights the group with Georgios and Martha. After being defeated, Sasaki and Georgios pretend to pass out because of their male pride. Martha ends knocking the two unconscious for real for this.
Subspecies Singularity III: Shimosa
In Chaldea, Sasaki joins Ritsuka and Mash’s discussion about Ritsuka meeting a female Musashi in a dream-like experience. He confesses he isn’t the real Sasaki, having never even met the male Musashi. However, since he was summoned as Sasaki, he was bestowed knowledge of the Book of Five Rings written by the male Musaashi. After describing the book, he asks if Ritsuka and Mash intend to use the Book to summon Musashi when he hears Ritsuka met a female Musashi. He asks them if she ever said “Kojirou, you have lost.” The male Musashi was said to have uttered that line after Sasaski casted aside his scabbard while awaiting Musashi on Ganryu Island. Sasaki suspects Ritsuka believed the female Musashi was Musashi because she uttered the line. Ritsuka responds that she never did, so Sasaki deduces she’s yet to reach the void. However, when he utters Musashi’s other name: ‘’Shinmen Musashi no Kami Fujiwara no Harunobu’’, Ritsuka falls into a coma. He goes to fetch Martha, and leaves Shuten-douji to keep an eye on things.
Assassin has minor appearances in Carnival Phantasm. The fact that he cannot go outside the temple is comically exaggerated, to the point of being replaced with a cardboard cutout in multiple scenes (including the opening theme). He is shown to be very attached to his gate, to the point he even talks to it, and apparently hears it talk back. He drives a Dekotora, which is large enough to carry his gate inside its trailer (and consequently allows him to somewhat leave the bounds of the temple).
Today's Menu for Emiya Family
Due to his inability to leave Ryuudou Temple, Assassin rarely appears in Today's Menu for Emiya Family. His first appearance is in Episode 4, when Shirou pays a visit to the Temple as part of a delivery. When Shirou decides to make a couple of sandwiches, he offers three slices to Assassin out of kindness. Assassin is delighted by the taste, so much so that he even asks Caster if she could make some more.
Just like in Carnival Phantasm, the anime's ending features Assassin as a cardboard cutout.
Tsuda, the Servant of Makki, is implied to be Kojirou as he is a samurai who can cut space and Tsuda is rumored to be the true name of the farmer who is playing the role of "Koujirou". Makki in turn is implied to be Yukika Saegusa.
- He was featured in Tank Man (戦車男, Sensha Otoko?), a parody film of Densha Otoko. Assassin plays the role of Medea's male caretaker. His role is expanded in TYPE-MOON 10th Anniversary Phantasm. Sasaki was calmly stating at how Medea was going crazy with an insect in her workroom, when her room was unhygienic. Medea knocks Sasaki out of the way and accidently knocks her modified Saber figure. He and Enkidu-chan was surprised when the other Eirei Throne Channel members suggested Sensha Otoko to buy a Saber figure for El-Melloi Girl.
- He was featured in the animated film Papillon Shin-chan ~I call for sleepiness! Spicy shaggy Kingdom~ (パピヨンしんちゃん〜眠気を呼ぶ！激辛モジャモジャ王国〜, Papiyon Shin-chan ~Nemuke wo Yobu! Gekikara Mojamoja Ōkoku~?), a parody film of Crayon Shin-chan.
The "Nameless Samurai" is not a Heroic Spirit, but rather, an existence closer to Wraiths. He was a nameless swordsman who existed in the same period as Miyamoto Musashi. His True Name was unknown, or to be more specific, he never had one. He is given the name “Sasaki Kojirou” due to being able to perform Tsubame Gaeshi, the technique said to have been used by Miyamoto Musashi’s legendary rival. Although it is unknown if the real Kojirou existed or not, it is thanks to being able to perform this technique that he can be summoned as an existence that fulfills the role of the imaginary Heroic Spirit; the nameless, genius swordsman. In the Fuyuki Holy Grail War which has been structured to have only “Hassan-i-Sabbah” summoned in the Assassin class, he is an irregular existence. Much like Gilles de Rais, Sasaki is an aberration in the normal Servant summoning process. It was only due to Medea acting as an unorthodox summoner and violating the rules by intervening with the system of the Holy Grail War that she was able to summon him as her Familiar.
Having been related in some way to the Ryuudou Temple in the past, its mountain gate was able to act as a Catalyst. Caster is unable to act as his anchor to the world due to also being a Servant, so he is instead bound to the land. The mountain itself acts as a host from the current age to keep him in the world. While that means that he cannot leave the mountain, it also means that he will not disappear even if his summoner dies. He can only appear on the mountain, and he will continue to exist as long as the mountain exists. He is not receiving constant magical upkeep, so he was only given twenty days worth of energy. He manages to go slightly longer than that limit in order to fight Saber, it is mostly luck that allowed that to happen. He begins to turn transparent, and will not last until dawn of that day.
Out of all the other Servants Artoria has seen, he seems incomprehensible to her, but not out of having fearful aspects or a fearful weapon. Her unease comes from not being able to sense any magical energy or even a Noble Phantasm, that it should be easy enough for her to end the match in one blow. Nothing special can be felt from his sword, so it should be easy for her to repel it. While she wishes to rush in and be done with it, her honed instincts can sense his ability to seize a sure kill, so she remains cautious of him.
He is very atypical as an Assassin. Servants in the Assassin class are normally the weakest ones in direct confrontation, and they defeat enemy Servants through covert actions or by killing their Masters to cut off their magical energy supply. Assassin does not employ assassination techniques such as ambush, and due to excelling in swordsmanship, he frequently chooses to fight face-to-face directly with other Servants. He does not gain the class ability of Presence Concealment due to not being a true Assassin-class Servant, but he does have the ability on his own. It is his intrinsic ability as a martial artist to “cut off his presence”.
In terms of pure swordsmanship, this Assassin, or “Sasaki Kojirou”, was not only the greatest in the Fifth Holy Grail War, but very likely, the most skilled swordsman in the history of mankind. When he was alive, he would hide himself away deep in the mountains and spend his days swinging his sword, with little interest in anything else. He never desired or attempted to show his hard-earned sword skills to anyone, so he was truly a nameless and meaningless existence. The popular notion that there are more people like him in this world than most realize took form as “the hope of the people” and produced sword skills capable of contending with Noble Phantasms. There is a Japanese proverb that says you can fend off any enemy if you have the right skills. Even if you can’t claim victory, you can at least chase them away. Kojirou’s style of defense is more of an offensive-defensive style, where instead of protecting himself from his opponent's strikes, he takes the stance of, “If you come any closer, I’ll probably die but I most certainly will take you with me.”
As a samurai, Kojirou is skilled in judo where he can deal with enemies while being unarmed.
He calls his sword a heresy, and says it will slice the head of one of average skill. Although a Servant of the Assassin class, he does not employ assassination techniques such as ambush, instead frequently choosing to fight face-to-face. During battle, Assassin counters the opponent’s attack with sword techniques and Mind's Eye (Fake), or simply by dodging. If he detects an opening, he would decapitate the opponent with the 5-shaku katana with certainty. Also, Assassin can deliver slashes even while standing idly, without assuming any stances. His technique is extremely swift, and very difficult to read. Due to having no skills in swordsmanship, if Gilgamesh were to fight Sasaki in close range, he would just defend himself with his armor or take out some really unfair defensive armament that protects against Multidimensional Refraction Phenomenon, from Gate of Babylon. However, Gilgamesh is capable of accurately assessing his opponents' abilities, so he would not consider having a battle of swordsmanship with Assassin the first place.
Assassin wields the Monohoshi Zao (物干し竿?, The Laundry-Drying Pole), an over five shaku long, 150 centimeter, Bitchu Aoe blade. The length defies common sense, the name being a derogatory nickname rather than a formal title, meaning “That blade is way too damn long to use!” It cannot be called "useful" despite its large range, as almost nobody except Assassin, having a mastery of the sword exceeding the realm of humans, could even wield it. The katana is a longsword not suited to direct competitions of power. It will break fighting off a sword like Excalibur, so he cannot lock blades or compete in strength. He can only parry blows and push the opponent back by attacking their body because the blade is meant to cut with speed and technique unlike western swords that cut with weight and power, making fighting styles between the two mismatched.
Fighting on the temple stairs gives him a higher position than his opponent, and due to the area being a Servant-killing battlefield and having Medea's anti-sorcery defensive barrier, the power of both magecraft and Noble Phantasms are decreased significantly. If the Noble Phantasm being used is not powerful, he will not take a fatal wound. While he would fall to other Servants in an all out death match, he reigns supreme on the stairs of the temple due to most battles having to come down to swordsmanship. The attacker is constantly at a disadvantage because they have to ascend the stairs to reach him, while he does not have to move if he does not wish. He has no need to chase a retreating enemy in a battle of defense, so he has no reason to forsake his advantage of higher ground. His excellent skill and the disadvantageous ground keep the opponent from being able to dodge his fatal strikes as they wish.
Throughout the Fifth Holy Grail War, Sasaki was able to repel the other five Servants without losing any ground. He was even able to push Heracles back because of the terrain advantage and support from Caster (weighing down Berserker's body). Nevertheless, since the compatibility of Assassin and Berserker is horrible, the fact that the Heracles was even pushed back is enough to say "whoah, Kojirou's amazing". Taking into account Kojirou's offensive-defensive style, if Heracles had gone in for the kill against Kojirou, Heracles would have been decapitated the moment his weapon reached Kojirou. Of course, Heracles has God Hand: Twelve Labors, so if he really had gone in for the kill, that would have simply been the end of Kojirou. However, knowing that Medea was behind him waiting for the right moment to strike, Illya chose to avoid charging in recklessly with Berseker. Although in a one-on-one duel, Kojirou vs Heracles wouldn't even be a fight, Medea would be able to use both Kojirou and Kuzuki as her two personal front-line Saber-class defenders, along with her high sorcery to to fight Heracles, but that would be limited to 2 to 3 times. Cú Chulainn comments that he wouldn't like fighting him one on one and would prefer to kill him off from a distance.
If EMIYA and Sasaki fought in a straight out death match, EMIYA would win. However, in a battlefield like Ryuudou Temple their fight would be reduced to the difference in their levels of swordsmanship. With Archer having his sniping sealed off to him due to the terrain effect, Archer would be at a clear disadvantage. Against Hassan of the Cursed Arm, if it's just Servant vs Servant, then without complaint, Cursed Arm would have the better chance of victory. Although Kojirou doesn't have any means of breaking through Zabaniya, there's more to it. The problem of Zabaniya is that it's not immediate death. If a normal heart gets destroyed by it, then the person dies immediately but the opponents are Servants. And especially against Kojirou, who has a strong spirit alignment, even if his heart is destroyed he still will has some fighting power left in him. Right in the interval after Hassan uses his Noble Phantasm, Assassin could close the gap and use Tsubame Gaeshi. Their duel would be technically a draw since both of them would end up dead. Caster placed a curse into his body upon summoning, allowing her to have his chest explode from within at her leisure. Even though his ribs are protruding from his chest, he is still able to act without fading away and later heal.
His strikes that aim for the head means that they must retreat instead of press forward, but the terrain of fighting on the stairs leaves them unable to dodge to the side. They are left retreating to the same spot, all the while he has no need to move from his position unless he wishes to unleash his ultimate technique. His swordplay is fast enough that even Saber has trouble following it. He works his sword like a hurricane, using elastic tracks to parry blows from opponents stronger and faster than himself, all while flowing toward the opponent's neck to decapitate the them with certainty should he detect an opening. Each of his attacks is fatal, meant to take the opponent's life by decapitation, so it is not possible to employ a strategy like taking a strike to then overpower him during the aftermath. He strikes with a curved path, a graceful arc that does not take the shortest route to the opponent like Saber's western sword.
- Presence Concealment (D Rank): Suppresses one's presence as a Servant. A Skill suitable for covert action. Since he is not a true Assassin servant, this is not a class ability. It is his intrinsic ability as a martial artist to “cut off his presence”. This is not a skill to hide, but a technique of the mind for the martial artist to merge with his surroundings. Because this is not a skill trained for assassination, it cannot match the Presence Concealment of Hassan of the Cursed Arm. In reality, a Kojirou Sasaki who cuts off his presence is an opponent that is hard to detect even for a Servant. It is extremely difficult to perceive Kojirou during the first encounter. However, because his activity is restrained to within the range of the Ryudo Temple Gate, those who know the existence of Kojirou can detect him relatively easily. With this said, due to Kojirou’s personality, battles are usually commenced only after the parties have presented and introduced themselves. As a result, this ability is rarely used for its original purpose.
- Mind's Eye (Fake) (A Rank): Premonition (“Spider-sense”) or sixth sense, very different from EMIYA’s danger avoidance originated from “predictions augmented by experience”. It may be called a natural talent to sense danger. During the Fifth Holy Grail War, in the battle with Artoria, Kojirou crossed blade with her invisible sword numerous times. He was able to use this ability to gauge even the length and width of the sword, and see through the fact that Artoria was unable to use her Noble Phantasm to attack due to a lack of mana. See through the weapon and style of his opponent after crossing blades only a few times, the perception of his eyes is the best among Servants.
- Knowledge of the Sowa (B Rank): A special ability that prevents the reduction of accuracy regardless of how many times the same technique has been used on one foe. In other words, it becomes impossible to see through any of his attacks. Although Kojirou and Artoria crossed blades numerous times, due to this ability, Artoria still could not adapt to Kojirou’s technique despite having Rank A Instinct. Paired with Kojirou’s unique “head-shot” techniques, the effect is vastly increased. No matter retreating and challenging him how many times, Artoria still cannot see through Kojirou’s techniques. She was always forced back to square one and fought as if it was the first encounter again.
- Vitrification (B+ Rank): An ability commonly called the “heart of clear water”. More precisely, it is a mental state acquired after reaching the pinnacle of arduous training. With this ability, Kojirou can maintain a cool and collected heart, regardless of the situation. Even when facing his very own death will not cause him to waver. During battle, mental interference such as charm and fear sorceries activated by the opponent is completely neutralized. For a “gate guardian”, this ability is certainly very useful. Like the many trees that surround the Ryudo Temple, Kojirou watches the gate in silence with a heart of clear water, just like an unwavering guardian. While he may not be an Assassin in the traditional sense and thus unable to make use of the Assassin’s ability of “Presence Concealment”, he is able to conceal his presence by utilizing a martial artist’s state of an empty mind.
Sasaki Kojirou’s ultimate attack is the technique that has reached the pinnacle of training and approaching True Magic --- Tsubame Gaeshi. Although it is a Mystery that rivals the Noble Phantasms of Servants, strictly speaking, this is neither a Noble Phantasm nor a magical phenomenon. The nameless martial artist who materialised as “Kojirou” sought nothing but the pinnacle of swordsmanship during his life. He trained himself in pursuit of swordsmanship, and doing nothing but swing his sword. After a long period of time, his technique finally reached another state. A flash from this world, followed by two absolutely simultaneous, over-lapping flashes that disregard the concept of time and space, producing a slash attack that arrives from three different directions. This is equivalent to Zelretch's “Multi-Dimensional Refraction Phenomenon” that transcends speed, dexterity, feint and many other elements. Although with some limitations, a nameless martial artist who knows naught of sorcery or True Magic is able to tread into the realm of the “Second Magic”.
In order to deliver the first strike as a horizontal slash, Kojirou must relinquish his high ground advantage over his opponent and move to an equal level before unleashing this technique. While Artoria believes that he will lose any advantage by doing so, she is misunderstanding his skill. From such a close distance, an opponent should be able to easily outmaneuver his longsword to get inside his range, but such logic does not apply to him. His attack should be unavoidable as long as there are no errors in its execution, making it a deadly technique able to overwhelm even Artoria.
While he holds out the thought that his sword may be able to block a few strikes from Excalibur, it is bent only after one clash. While it is a good sword able to cut steel, something made by a human cannot compare to something not made by men. He utilizes the method to force Saber onto flat ground to utilize Tsubame Gaeshi, but it proves to be his undoing due to the bend in the sword allowing for a gap for Saber to escape from the technique.
Musashi believes that as a swordsman, Kojirou has already reached the state of emptiness. It is said that there is no swordsmen that can reach Infinity, a path that surely no one can ever walk upon.
Forms and Alternate Versions
Sasaki Kojirou encounters Musashi after the latter's duel with Munenori, and the two warriors would enter their fated duel. Their blades clash, and their power and skill are equal. Both their swords transcended time and space, yet their existence and concept are the exact opposite. The clash of the existences and concepts between Kojirou's Infinity and Musashi's Zero creates an infinite place, or perhaps, an empty place, where there is no time, space, karma, good or evil. A situation only those two who put their very souls into their blades can reach. Simultaneously, both of them surpass Infinity. Both of them would continue to try to kill each other over and over again for all of eternity. It is not the real world, and this moment will never be recorded or stopped for anyone. This place lies between the real world and the world of dreams. An impossible place where Infinity and Zero can intersect. A miraculous sword fight that is supposed to go on forever, never reaching its conclusion. But due to Ritsuka Fujimaru's presence and deciding his/her winner, Musashi was able to win the duel against Kojirou, the sword of Zero having destroyed the sword of Infinity.
Being the only swordsman who can wield "The Laundry-Drying Pole", Nameless Saber has undoubtedly reached the pinnacle of swordsmanship. Even Amakusa Shirou, who burns with loathing for the world and everything in it has some respect for Saber's skill, claiming there is no demonic sword in the entire human realm that surpasses his. Due to this, as long as Saber is by his side, he considers he has nothing to fear from Miyamoto Musashi.
Nameless Saber is an exceptional swordsman just like Saber of Empireo and just from looking at him, Musashi immediately recognizes his identity as his fated ultimate rival, Sasaki Kojirou. Before their swords ever clash, Musashi also claims that his skill is godly and that he's at least several times stronger than her.
As their blades clashed, their power and technique seemed evenly matched. Not only that. Their skills had surpassed everything; time, space, existence, essence. Each being the other's perfect mirror image. Through "history's greatest duel", their duel would have prolonged for eternity had Ritsuka Fujimaru not determined Musashi as the winner.
Skills: In the game, he possesses the same Personal Skills as his Assassin counterpart:
- Mind's Eye (Fake) (A Rank)
- Knowledge of the Sowa (B++ Rank)
- Vitrification (B+ Rank)
- Tsubame Gaeshi: There is a sword of infinity that leads to multiplicity. A way to acknowledge "multiple possibilities". A single act that is originally finite; a single slash that can only be performed at one time, in one space. It is, so to speak, an "infinite" sword that gives birth to several "correct answers". To make one's own existence transparent to the extremes, until there is nothing more. And yet to grasp for "something" beyond that. That is Kojiro's "Tsubame Gaeshi". A sword that creates a "future" that not even the gods can escape from.
- In the first Popularity polls of Fate/stay night in 2004, Assassin was ranked 14th.
- In the second Popularity polls of Fate/stay night in 2006, Assassin was ranked 25th.
- In the Type-Moon's 10th Anniversary Character Poll, Assassin was ranked 63rd.
In Fate/Grand Order, Assassin is named as part of a dragon slaying trio due to the various online memes revolving around him being a fellow "dragon slayer" during the France chapter. The affinity of the Assassin class over the Rider-class dragons made him an easily accessible unit during the chapter, so he was made part of the trio despite not actually appearing in-story during the chapter.
 Fate/complete material II: Character Material - Characters: Assassin, p.088-089
Character Data 014
Affiliation: Caster's Servant
True Identity: Kojiro Sasaki
Image Color: Cobalt blue
Likes: Flowers, Birds, Wind, Moon
Dislike: None in particular
Worst enemy: Zouken Matou, Sakura Matou
Nasu Kinoko & Takeuchi Takashi • Character Discussion
>The catalyst for Assassin's birth
Nasu: Assassin is the ultimate in straightforward characters... there are no twists or surprises to him...
Takeuchi: I don't think we need to emphasise that... (laughs)
Nasu: We used some pretty identifiable East/West archetypes for the Servants, and you recognise Assassin as a samurai as soon as you see him. In addition, the one rule that had always been at the forefront of all things Master and Servant-related was the fact that servants tend to hide their true identities by default. Then along came Assassin, who did not hesitate to introduce himself as Kojirou Sasaki. I was aiming for the ultimate "surprise" factor by blatantly breaking the mold with Assassin... that's really the only motivation I had for his character.
Takeuchi: You sound like you're devaluing him entirely. (laughs)
Nasu: I also really wanted to attach him to the mountain gate because mountain gates are such a regular feature in legends. Such gates tend to be guarded by scary demons, and Assassin's presence around Ryuudouji Temple is like an homage to those legends because he is attached to the gate instead of a Master, like other Servants. His role as the gate's guard serves another purpose... I think all RPG players are familiar with the notion of wanting to get to their main target, but being forced to fight through other enemies first. Assassin is that very wall standing between an intruder and their main target inside Ryuudouji Temple.
>Regarding Assassin's design
Takeuchi: Assassin is such a stoic character. His design was based on a design I thought up for old "Fate".
Nasu: But the character design used in old "Fate" had more of an otherworldly and feminine vibe, didn't it?
Takeuchi: Yeah, this Assassin is definitely manlier compared to the previous iteration.
Nasu: The old "Fate" design possessed a kind of undeniable beauty that appeals to both men and women.
Takeuchi: That type of beauty was really popular back when you and I were still in school. Hideyuki Kikuchi's "Makai Ishi Mephisto" is one example that instantly comes to mind. Our old Assassin was based on that theory of beauty... one that transcends the usual boundaries of male and female aesthetics, which some consider to simply be a man with a pretty face. Though Assassin's "beauty" is not enhanced with the appeal of the demon world Makai, I fully intended for him to be the most handsome character in the series.
Nasu: I guess you could say Assassin was beautiful in old "Fate" and handsome in this one.
Takeuchi: Less elegance, perhaps, but definitely more purity. The current Assassin lost some of that sense of divinity he had in old "Fate", and instead gained a generous helping of godly swordsmanship skills.
>Assassin's skill as a swordsman
Nasu: This Assassin, or "Kojiro Sasaki", could possibly the most skilled swordsman in the history of mankind. He was the kind of guy who would hide himself away deep in the mountains and spend his days swinging his sword, with little interest in anything else. But he never desired or attempted to show his hard-earned sword skills to anyone. The popular notion that there are more people like him in this world than most realise took form as "the hope of the people" and produced sword skills capable of contending with Noble Phantasms.
Takeuchi: In old "Fate", it was the Kojiro Sasaki from the Musashi Miyamoto legend who was summoned, right?
Nasu: In old "Fate", yes. Though both were summoned by Caster, the Kojiro Sasaki in old "Fate" was the real deal. But during my 15 years since I wrote old "Fate", I've been able to read up some more on Kojiro's legends, and it turns out there's a theory that the legends are compiled from the feats performed by three different individuals. Based on this, I thought it would be interesting if this Assassin was a "Fake" Kojiro. If a Master were to try and intentionally summon Kojiro Sasaki, they wouldn't be able to because he didn't actually exist. As was suggested in the storyline, if there existed a giant database of humans, this swordsman would be the one whose data most closely resembled the profile of "Kojiro Sasaki". Through this process, this man's persona became that of Assassin's (Kojiro Sasaki's), and any accomplishment he achieved would therefore be attributed to Kojiro Sasaki rather than this random "nameless samurai". This "reality shift" of sorts is also why a mere human being was able to master a move like the "Multi-Dimensional Refraction Phenomenon (Tsubame Gaeshi)". Still, he himself does not particularly view this feat as anything special. He does recognise how it could be considered impressive, but in his opinion, it is completely reasonable for a man to produce such results if they spent over 50 years swinging a sword and doing little else.
Takeuchi: I find that most gifted people tend to have similar misconceptions.
Nasu: I will also note that this particular individual was capable of performing the Tsubame Gaeshi while he was still alive as a mortal, so it is not a skill he acquired as a Servant. He literally mastered the ability right at the end of his lifespan, and died with the satisfaction of knowing that he had reached the pinnacle of swordsmanship. So despite achieving this feat before his natural death, he was at no point intentionally aiming for something as grand as the Multi-Dimensional Refraction Phenomenon, nor did he ever show another living soul what he had learned. Can you imagine? He achieved something that would be considered impossible for a human being under normal circumstances, yet his reaction was to nod and say, "I suppose that will do" before keeling over. This is just the way he was, and basically sums up why he is a miracle man.
>The message Assassin carries as a character
Nasu: Uhm... I actually think we've covered everything already.
Takeuchi: Kojiro almost vanished completely, but somehow he managed to cling to this realm of existence for the sole purpose of sharing a battle with Saber. So I guess you could say he was one of the most single-minded and stubborn characters?
Nasu: For the entire duration of his life as a mortal man, Kojiro never once exchanged blades with another living soul. So getting the opportunity to fight against a warrior who he deemed worthy was truly a special occasion for him. As a side note, Kojiro even fended off Berserker once. There is a Japanese proverb that says you can fend of any enemy if you have the right skills. Even if you can't claim victory, you can at least chase them away. Kojirou's style of defense is more of an offensive-defensive style, where instead of protecting himself from his opponent's strikes, he takes the stance of, "If you come any closer, I'll probably die but I most certainly will take you with me". If Berserker had gone for the kill against Kojiro, Berserker would have been decapitated the moment his weapon reached Kojiro. Of course, Berserker has God Hand: Twelve Labors, so if he really had gone for the kill, that would have simply been the end of Kojiro. But Illya knew Assassin had Caster behind him, so she chose to avoid charging in recklessly with Berserker.
Character Data ０１４
奈須 きのこ&武内崇 • キャラクター別対談
 Fate/complete material III: World Material - The Servants of the Fifth Holy Grail War: Assassin, p.034-035 [T]
Alignment: Neutral Evil
Noble Phantasm: ??
Kojiro Sasaki. A Japanese man without a real identity, and it may not be an overstatement to say that he has never existed. He was described as the rival of Nitoryu sword master Miyamoto Musashi, and a handsome swordsman who skillfully wielded the 3-shaku-long (approximately 1m) nodachi “Bizen Osahune Nagamitsu” which is also called “Monohoshi Zao”. His duel with Miyamoto Musashi at Funajima Island, such lines as “Kojiro has been defeated!”, and the finale of death by having his forehead crushed by an oar are all legendary. Although he was said to be the disciple of Chujoryu kodachi master Toda Seigen, there are numerous conflicting documentations and legends, which still shroud his true identity even now.
The “Kojiro Sasaki” summoned in Fate/Stay Night is not a Heroic Spirit. He is an existence closer to wraiths. He was a nameless martial artist given the name Kojiro Sasaki. What his real identity was, there is no way to know. He seemed to be related to the Ryudo Temple. He uses a long Japanese katana and discovered the ultimate technique “Tsubame Gaeshi”... and these are absolutely all he possesses. His pursuit of sword technique, sophistication, and finding joy in duelling with strong foes are all reminiscent of the legendary Kojiro Sasaki: cool and elegant.
Assassin’s differences with Kojiro are that, his katana is longer (approximately 1.5m), and the engraving on the katana is “Bitchu Aoe” (Blue River of Bitchu).
Although a Servant of the Assassin class, he does not employ assassination techniques such as ambush, instead frequently choosing to fight face-to-face. During battle, Assassin counters the opponent’s attack with sword techniques and Eye of the Mind, or simply by dodging. If he detects an opening, he would decapitate the opponent with the 5-shaku katana with certainty. Also, Assassin can deliver slashes even while standing idly, without assuming any stances. His technique is extremely swift, and very difficult to read. Kojiro Sasaki’s ultimate weapon is the technique that has reached the pinnacle of training and approaching True Magic --- Tsubame Gaeshi. It is an attack that delivers 3 slashes simultaneously, enough to overwhelm even Artoria.
Presence Concealment: D
Since he is not a true Servant Assassin, this is not a class ability. It is his intrinsic ability as a martial artist to “cut off his presence”. This is not a skill to hide, but a technique of the mind for the martial artist to merge with his surroundings. Because this is not a skill trained for assassination, it cannot match the Presence Concealment of Hassan. In reality, a Kojiro Sasaki who cuts off his presence is an opponent that is hard to detect even for a Servant. It is extremely difficult to perceive Kojiro during the first encounter. However, because his activity is restrained to within the range of the Ryudo Temple Gate, those who know the existence of Kojiro can detect him relatively easily. With this said, due to Kojiro’s personality, battles are usually commenced only after the parties have presented and introduced themselves. As a result, this ability is rarely used for its original purpose.
Eye of the Mind (False): A
Premonition (“Spidey-sense”) or sixth sense, very different from Emiya’s danger avoidance originated from “predictions augmented by experience”. It may be called a natural talent to sense danger. During the Grail War, in the battle with Artoria, Kojiro crossed blade with an invisible sword numerous times. He was able to use this ability to gauge even the length and width of the sword, and see through the fact that Artoria was unable to use her Noble Phantasm attack due to a lack of mana.
See through the weapon and style of his opponent after crossing blades only a few times, the perception of his eyes is the best among Servants.
An ability commonly called “heart of clear water”. More precisely, it is a mental state acquired after reaching the pinnacle of arduous training. With this ability, Kojiro is able to maintain a cool and collected heart, regardless the situation. For example, even facing his very own death will not cause him to waver. During battle, mental interference such as charm and fear sorceries activated by the opponent is completely neutralised. For a “gate guardian”, this ability is certainly very useful.
Like the many trees that surround the Ryudo Temple, Kojiro watches the gate in silence with a heart of clear water, just like an unwavering guardian.
Knowledge of Respect and Harmony: B
A special ability that prevents the reduction of accuracy regardless how many times the same technique has been used on one foe. In other words, the ability to “render one’s attacks unreadable to the enemy”. Although Kojiro and Artoria crossed blades numerous times, due to this ability, Artoria still could not adapt to Kojiro’s technique despite having Rank A Instinct. Paired with Kojiro’s unique “head-shot” techniques, the effect is vastly increased.
No matter retreating and challenging him how many times, Artoria still cannot see through Kojiro’s techniques. She was always forced back to square one and fought as if it was the first encounter again.
The ultimate sword technique that assaults the opponent from three directions “simultaneously”. Strictly speaking, this is neither a Noble Phantasm nor a magical phenomenon. The nameless martial artist who materialised as “Kojiro” sought nothing but the pinnacle of swordsmanship during his life. He trained himself in pursuit of swordsmanship, and doing nothing but swing his sword. After a long period of time, his technique finally reached another state. A flash from this world, followed by two absolutely simultaneous, over-lapping flashes that disregard the concept of time and space, producing a slash attack that arrives from three different directions. This is the “Multidimensional Refraction Phenomenon—Kischua Zelretch” that transcends speed, dexterity, feint and many other elements. Although with some limitations, a nameless martial artist who knows naught of sorcery or True Magic is able to tread into the realm of the “Second Magic”.
The range of this skill is approximately 3m. In order to deliver the first strike as a horizontal slash, Kojiro relinquished his high ground advantage over Artoria and moved to an equal level before unleashing this technique. You may discern how special a secret technique “Tsubame Gaeshi” is to Kojiro, who never assumes a stance, by observing how he lifts his sword and then swiftly launches the technique.
- Fate/Grand Order material II - Kojirou Sasaki, p.006-011 translated by castor212
 Fate/Grand Order - Assassin Profile [T]
Kojirou Sasaki - Assassin
Illustrator and Voice actor
Voice Actor: Shinichirō Miki
Eye of the Mind (False): A
Presence Concealment: D
Type: Anti-Unit Mystic Sword
A swordsman described as a worthy rival of one of Japan's prominent master fencer - Miyamoto Musashi.
Mastering the Ganryuu-style at a young age, a genius swordsman said to find no equal no matter where he went.
Level 1 Bond
Source: Historical fact
Alignment: Neutral Evil Gender: Male
"No matter who may be, one is evil from the moment he cuts down a person."
Level 2 Bond
A refined man who admires the beauties of nature and wraps his body in an elegant battle surcoat.
Aloof from the world and having a somewhat elusive personality but, as expected, he is a warrior who likes fair and square contests.
Due to living in a age where casualties happened in a daily basis, his perspectives about life and death may also seem cold-hearted for a modern person.
Level 3 Bond
- Tsubame Gaeshi
Anti-Unit Magic Sword. Maximum Targets: 1 person.
A sword technique that rivals Noble Phantasms, attained only with human techniques.
A special move that simultaneously cuts apart an enemy with three circles.
Seems to be one of the things that can be called multi-dimensional refraction phenomenon.
Originally, it was something developed to cut a swallow flying on the sky.
Level 4 Bond
He himself calls it a secret sword technique, but on the eyes of the surroundings it is unmistakably a magic sword.
For that is not the work of man.
He himself says that it was developed for cutting a flying swallow, but, of course, it is possible to cut a swallow even without a mystic technique such as this.
Rather, this is a story about the lack of compromise, and also, how much extreme talents for martial arts was possessed by this swordsman - who reached the blessings of the sword just for such a reason.
Level 5 Bond
Souwa's Understanding: B
A unique ability that prevents drop on hit-accuracy no matter how much the same technique, the same sword skill is employed against an opponent.
It becomes impossible to see through attacks.
"The eyes grow used to the attacks"; maybe it means that such inferior sword swings are not unleashed.
Unlike Musashi, Sasaki Koujirou is a fictional swordsman whose real life is indefinite.
This "Sasaki Koujirou" is nothing but an nonentity swordsman that was summoned due to the fact he can reproduce the "Tsubame Gaeshi" that appears in Koujirou's legend. The mental state of this genius swordsman - who remained anonymous for life, and was summoned in order to fill up for a fictional Heroic Spirit - is, of course, "that is fine too" it seems.
佐々木小次郎 - アサシン
- Tsubame Gaeshi
 Fate/side material - Encyclopedia: Assassin [Servant], p.055 [T]
Heroic Spirit of assassination.
Different from other Classes, only certain Heroic Spirits qualified for Assassin.
He was the samurai who guarded the mountain gate of Ryuudou Temple.
Sasaki Kojiro was summoned into this class because a certain unorthodox summoner violated the rules.
Strictly speaking, Assassin was a Wraith rather than a Heroic Spirit.
He seemed to be a martial artists who had connections with the Ryuudou Temple in the past.
His true name was unknown. To be more specific, he never had a true name.
Perhaps because he never had the possibility to become a liege, he had no ambitions. He lived only for the wish to stand in the inner sanctum of swordsmanship, and eventually he achieved a Mystery that rivaled the Noble Phantasms of Servants.
In terms of pure swordsmanship, he was the greatest in this Holy Grail War.
Since he was summoned with the mountain gate as the catalyst, he could not leave the gate.
...Huh? Almost like a Jibakurei eh?
- Nasu: If a Master wished to summon Kojiro Sasaki, he would be unable to because Kojiro Sasaki did not exist. Like the story stated, if there were a database for humanity, then Assassin was the piece of data that matched the parameters of Kojiro Sasaki. As a result, Assassin's personality would become Kojiro's personality, and Assassin's monumental feats would become that of Kojiro's rather than his.
 Fate/stay night [Unlimited Blade Works] Animation Material I - Kinoko and Takashi Q & A, p.041 [T]
Q: Sasaki Kojirou spent his entire live sword training in the mountains, so how did he acquire a sword like the Bitchu Aoe (Blue River of Bitchu)? Was he not spending his time farming on the farmlands?
Q: Sasaki Kojirou spent his entire live sword training in the mountains, so how did he acquire a sword like the Bitchu Aoe (Blue River of Bitchu)? Was he not spending his time farming on the farmlands? <Sunday>
Nasu: Kojirou is the son of a ordinary farming family, living an ordinary farm life and separated from ordinary common sense. Ordinarily He met a master swordsman who had retired deep into the mountains, and began his ordinary life in the mountains himself. He was enthralled by the swordsmanship of the master, and he began training under him the next day. After one month, the master swordsman drew his last breath, and Kojirou completely threw himself into the path of a swordsman. By the way, what the master swordsman talked on about was the refined behavior of a swordsman--a communion with nature, so to speak. He did not instruct Kojirou on anything related to sword techniques. The Bitchu Aoe may have been the master's, or perhaps he received it from the Holy Grail when the legendary soul was summoned. It is simply something thought to be part of who he is.
Takeuchi: So he only witnessed the opening of a performance [referring to swordmanship]... so he's really a genius among geniuses isn't he!?
Nasu: Isn't it obvious. Don't underestimate a chivalrous man person who is eligible as a Servant despite being nameless. He was raised in both mind and body in those mountains. Even without a katana that master swordsman can cut through dimensions. Sengo Muramasa, that which can cut even casualty.
佐々木小次郎は生前ずっと山で剣を振るだけの人生を過こしたそうですが、そうするとどうやって備中青江のような業物を手に入れたので しょうか？というか、ちゃんと農民として農作 業をしたりしてたのでしようか？ ＜Sunday＞
奈：あの男はフツーの農家の子供で、フツーに村の暮らしとか人間の常識からズレていて、フツーに山奥に隠れるように隠居した剣聖に出会い、フツーに山で暮らすようになったんだ。はじめて剣聖の太刀筋を見た時に心奪われ、翌日から弟子入りするも剣聖はひと月ほどで息を引き取り、後はいびつながらも純粋に剣の道を究めた。ちなみに、剣聖が話してきかせたものは剣士としての雅な立ち振る舞いーーー即ち花鳥風月のみ。剣に関しては佐々木某に何一つ教えなかつた。備中青江は剣聖の持ち物か、 あるいは英霊と して召喚された時に聖杯から与えられた。佐々木小次郎としての出で立ち、と思われます。
 Fate/complete material III: World material - FAQ with Nasu: Servants, p.133
Q: Did the man known as Sasaki Kojirou have a real name?
Q: Did the man known as Sasaki Kojirou have a real name?
A: There is speculation that Kojirou’s real name was Tsuda, etc., but the man known as Assassin has no name.
 Fate/complete material III: World material - FAQ with Nasu: Command Spells, p.132
Q: After Caster summoned Assassin (Sasaki Kojirou), was she branded with Command Seals?
Q: After Caster summoned Assassin (Sasaki Kojirou), was she branded with Command Seals? I ask because I don’t think she ever used a Command Spell on Assassin.
A: She had something similar to a Command Spell. Though, as a fake Master with a fake Servant, it wasn’t something as powerful as a true Command Spell. While she may not originally have received any Command Spells, Caster may have skillfully borrowed the power of the Greater Grail to forge herself an imitation.
- Fate/Grand Order - Sasaki Kojirou's interlude 01: LEGEND OF THE SAMURAI
 Fate/Zero material - Encyclopedia: Gilles de Rais [Servant], p.097-098
Gilles de Rais [Servant]
A nobleman from 15th Century France. As a leader in the French army, he fought alongside Jeanne d'Arc to put an end to the Hundred Years War, and was hailed as a hero who saved his country. But soon after he returned to his territory, he began kidnapping, raping, and killing young boys one after another, eventually coming to be feared as the villain "Bluebeard".
However, it was all-too-common in that era for nobles to disregard the human rights of commoners and treat the populations of their territories as disposable livestock. So, under normal circumstances even killing them en masse shouldn't have been treated as anything more serious than animal abuse. But unfortunately for Gilles, he had an enormous amount of land holdings at the time, far exceeding those held by the Duke of Brittany, and enough to be regarded as a threat by the king himself. On top of that, due to his mind-boggling wastefulness in his private life, his public finances were almost entirely depleted, and there were apprehensions that he may try to sell his land to enemy nations. As a result, he was condemned and executed for his crimes as a pretext for seizing control of his assets.
As for Gilles' relation to sorcery, he turned to alchemy in an attempt to relieve his financial difficulties, and eventually strayed down a dark path that led him to try summoning a demon. But while it's certainly true that he participated in the ceremony, the actual magus was his friend François Prelati – Gilles himself was nothing more than a patron. As such, he is not a Heroic Spirit that qualifies for the Caster class. Or rather, he is not even a proper Heroic Spirit at all. The fact that Ryuunosuke's bogus ritual ended up actually completing a summoning sorcery was, honestly, more or less a total fluke. In that sense, the "Caster" Gilles de Rais is just as much of an irregular Servant as the "Assassin" Sasaki Kojirou.
 Comptiq 2007-11 issue - Fate Dojo Q & A:
Q: Gilgamesh has no skills in swordsmanship, would Assassin win if Gilgamesh is caught in the range of Tsubame Gaeshi?
Q: Gilgamesh has no skills in swordsmanship, would Assassin win if Gilgamesh is caught in the range of Tsubame Gaeshi?
A: Most likely, he will just defend with his armour, or take out some really unfair defensive armament that protects against Multidimensional Refraction Phenomenon, from the Gate of Babylon. However, Gilgamesh is capable of accurately assessing his opponents' abilities, so he would not consider having a battle of swordsmanship with Assassin the first place.
 Fate/complete material II: Character material - Weapons: Monohoshizao, p.138
The Laundry-Drying Pole
Long sword used by Assassin. Measuring 5 shakus (about 1.5 meters), its length defies common sense. Though it has a huge range, it can’t really be called “useful”. Probably nobody except Assassin himself, whose mastery of the sword exceeds the realm of humans, is even capable of wielding it.
It was the sword used by Sasaki Kojirō in real life, as well. The name “Laundry-Drying Pole” is not its formal title, but more of a derogatory nickname. “That blade is way too damn long to use!” would be the intended meaning.
アサシンが使用する長刀。長さ五尺（約1m50cm）という常識外の長さを誇る。間合いは広いが使い勝手 がいいとはとても言えす、人の域を超えた剣技を会得したアサシン以外には使いこなせないだろう 。
- Fate/Grand Order - Miyamoto Musashi's My Room Lines, Dialogue 4
- Fate/Grand Order - Musashi's Trial Quest: Wanderer
- Fate/Grand Order Epic of Remnant - Shimosa Province: The Stage of Rivers of Blood and Mountains of Corpses - Act 15: Duel between Musashi and Kojiro