Imperial Tokyo Singularity

GUDAGUDA Strange Tales of the Imperial Holy Grail (ぐだぐだ帝都聖杯奇譚) refers to an event which occurred during the aftermath of the Human Order Incineration Incident. It involved a Singularity created at the coordinates of Tokyo in 1945.

Setting
Akechi Mitsuhide transformed Tokyo into a Singularity by placing fragments of a Holy Grail at certain coordinates on the leyline in a wedge formation. He sought to create a Saint Graph that would become what he would declare as the true Oda Nobunaga. In order to achieve his goal, he initiated a Holy Grail War to assemble a massive number of Servants. However unlike a regular Grail War, the Servants have no Masters, and instead fight to earn class titles. Once a Servants earns a class title, they are permitted to create territories inside the wedge formation formed by the Grail fragments called a Red Line. If the proper owner of a class title stays with their Red Line, their mana is constantly replenished, and they're bestowed with the Grail's blessing. Because of this, Servants seek to expand their territories by seizing of other territories to increase their blessing from the Grail. By the time of Chaldea's involvement, this Grail War already repeated itself many times.

In truth though, all of Tokyo is Akechi's Red Line, and the Servants' mana is accumulated into the Grail every time the war repeats. This is for the purpose of forging a Saint Graph of the highest purity. Seeking to create his ideal Nobunaga, Akechi used to the Grail to forcefully summon Nobunaga to eventually serve as the catalyst. Nobunaga sensed this though, and cut herself before her Saint Graph fully materialized itself. She then used her own Saint Graph to summon Nobukatsu to serve as her vessel in an emergency.

Considering Akechi's ritual to be a threat, the Counter Force deployed Sakamoto Ryoma and Oryou into the Singularity. Ryoma and Oryou eventually killed the official Rider, and proceeded to investigating the Servants' Red Lines. Okita Alter was also summoned into the Singularity to serve as a Counter Guardian once for the purpose of stopping Akechi to repay Okita Souji's debt from when the World stopped her illness from claiming her as a child. Unfortunately though, she was summoned without any memories and knowledge of the ear, along with poor combat skills and initially the inability to speak.

History
At the conclusion of a certain war, Nobunga Oda and Okita Souji face off against each other,; the latter being in poor condition. Nobunaga betrayed Ritsuka for standing in the way of ambitions. She declares none can stop her from using the Maxwell Reactor to destroy Okita, and rewrite history as her paradise. Okita realizes that is why Okita realizes that is the reason Lady Chacha, Hijikata Toshizō, and Ritsuka had to die. Nobunaga prepares to kill Okita when a mysterious light appears before the latter. Okita then uses it to become Okita Alter. Later in Chaldea, Okita Alter explains the previous events to Ritsuka, Nobunaga, and Chacha. However the scene is revealed to be her viewing a memory of Chaldea.

Ritsuka suddenly rayshifted to a city. They're found by a citizen who tells them to run since the alarm is going off. Ritsuka learns from him that they're in Imperial Tokyo when a Nobbu suddenly appears. They run upon seeing the Nobbu massacre several citizens. However they bump into someone they assume to be Nobunaga, who shoots them. Nobunaga assumes they were summoned by Caster, and tries to kill them. Her bullets are blocked though by Okita Alter. Nobunaga assumes she is Ritsuka's Servant, and fights her to test her capabilities as a Servant. She is disappointed though by her lack of strength, and prepares to kill her. However, a woman accompaning a man blocks her bullets. The group then run, with the woman carrying Ritsuka, while being chased by Nobbu. After escaping, the man assures the bullet didn't any of Ritsuka's vital organs. He then introduces himself as Sakamoto Ryoma.

At a certain place in the city, an officer reports to General Omami that Servants were spotted within the Red Line. The three Servants were identified as Saber, Archer, and Lancer. Saber is a female swordsman, Lancer is a samurai spearman, and Archer is Nobunaga. Omani asks for a progress report on the Heroic Spirit army. The officer reports two platoons have been formally approved and posted within the imperial capital for the purposes of security and surveillance. Omami orders him to continue the surveillance for the sake of the capital, then permits him to leave. After the officer leaves, Omami laughs at himself maniacally that Nobunaga has returned.

Ritsuka wakes up in an old detective agency that Ryoma is using. Ryoma introduces the woman as his assistant, Oryou. He explains they are currently in a Holy Grail War without Masters,where the Servants compete for a class title. He specifies the Servants fighting for a class title are more like failure fighting to become a real one, comparing it to a preliminary round. Leonardo da Vinci and Mash Kyrielight then make contact to Ryoma's surprise since Tokyo is quarantined. Da Vinci realizes the quarantined space of Tokyo was the reason they couldn't locate Ritsuka after they were rayshifted. Ryoma exxplains his goal is to either retrieve or destroy the Grail. Da Vinci then reveals Tokyo is in an isolated spaced surrounded by an invisible barriers that prevent both entry and exit. Ryoman confirms neither Servants nor humans can leave. Da Vinci assures Mash that Ritsuka can be rayshifted back since they were able to contact them. However, more information and stability is required to increase the success rate. Da Vinci deduces a fews points on the leyline form the barrier that maintain Tokyo's space and time. She identified a few coordinate that Ryoma agrees to investigate. A third party then starts to interfere with communications, so she sends the coordinates before communications are cut. Ryoma then prepares to leave to check on the other Servants' movements. He explains that when the proper owner of a class title stays within the Red Line, they are bestowed with the Grail's blessing. Because of this the Servants try to take each other's territories. After leaving, Ryoma is left troubled by Okita Alter's identity.

Ritsuka and Okita Alter listen to a radio broadcast announcing that the army's 4th Division of the Magus Facility will initiate a Holy Grail War at a unspecified time. Okita Alter is concerned she doesn't have any memories of her past, and questions if she really is Okita. She also lacks knowledge of the era, and she couldn't speak until a moment ago. She then sense someone coming when a man enters asking if he's at Ryoma's place. Ritsuka confirms thus, so the man tries to kill them. Okita Alter blocks his attacks, but he ridicules her for her weakness despite being a Saber. He attacks her, but she manages to defend herself as he mocks her swordsmanship. Seeing they're at a disadvantage, Ritsuka and Okita Alter escape.

Ritsuka and Okita Alter escape to the street, but the man easily catches up. He tries to attack them, but Oryou blocks him. Ryoma identifies him as Okada Izou, who tries to attack Ryoma for betraying him in life. His attack is again blocked by Oryou. Ryoma then dodges an attack from Okita whose been pursuing him for crossing her Red Line. She becomes confused upon seeing Okita Alter. She tries to chase after the group when they escape, but her illness stops her. She realizes Okita Alter is the same as her.

At the detective agency, Ryoma allows Izou to strike him as a revenge for his betrayal. After being healed, he reveals he located a few coordinates with fragments of the Grail installed in a wedge formation. It is meant to be utilized by the Servants, and where they set establish their Red Lines. Ryoma explains Servants fighting for territorial supremacy is the rule of the Grail War. Da Vinci concludes that since the Singularity is maintained by the Grail fragments, it will be corrected once they're destroyed. Before communications are cut off again, she explains the wedges and Red Lines act in parallel to each other. This means the less territory a Servant has, the weaker their blessing from the Grail is. Ryoma states their next objective is to take down the Red Lines, then destroy the Grail Fragments. He then convinces Izou to help by mentioning that Okita and another Shinsengumi member will be tought opponents.

Izou protects Ritsuka and Okita Alter as they head to Lancer's Red Line. They soon arrive at Lancer's Red Line, but Izou becomes concerned when Lancer's presence suddenly disappears. He then senses another presence, and he has Ritsuka and Okita Alter follow him inside. There they're greeted by Li Shuwen, who just killed the official Lancer is a single strike. He and Izou then fight each other. Meanwhile, Ryoma and Oryou investigate a site when they're spotted by Hijikata Toshizou. At the same time, Izou is losing against Li Shuwen. He realizes Li Shuwen is now the official Lancer. Seeing Izou is unable to fight, Ritsuka orders Okita Alter to fight despite Izou's objections. Despite her amateur swordsmanship, she manages to fatally wound Li Shuwen. After he disappears, Okita Alter realizes her movements had improved when she saw Okita earlier. The group then leave.

At a certain office, an officer reports to Omami that Lancer's Red Line has been eradicated. He posits that Assassin is responsible for Lancer's death while injured himself. Afterwards he escaped while covering their tracks and hiding from the army's surveillance. Omami tells him to leave Assassin be since he won't last long injured. After the officer leaves, he prepares to leave himself, stating Nobunaga's feast has been fully prepared.

After Ritsuka and Okita Alter return to the detective agency, Ryoma tells them he found Hijikata. Da Vinci confirms the wedge under Lancer's control has been destroyed. Ryoma wasn't able to defeat Hijikata, so he'll try to destroy his wedge tomorrow. Da Vinci explains that with every wedge destroyed, the interference gets weaker. After communications with Chaldea are again cut, Ryoma notices Izou isn't around. Ritsuka tells him what happened, so he decides to leave it be for now.

Meanwhile in Nobunaga's Red Line, she meets with Caster's assistant. She is handed an agreement of cooperation that she has Oda Nobukatsu read. The agreement calls for a ceasefire between Nobunaga and Caster until all Servant except them are eliminated. Once that is done, he will give the Grail to her. While she and Nobukatsu are suspicious, Nobunaga accepts Caster's terms regardless. After the assistant leaves, Nobunaga reveals she knows Caster will betray her in the end.

At the detective agency, Ryoma reveals he was able to locate Okita and Nobunaga thanks to Chaldea's intel. He was unable to locate Caster though, so they'll have to wait for them to make a move to get a lead. Okita Alter decides to go after Okita, while Ryoma and Oryou decides to go after Nobunaga. After they leave, Ritsuka and Okita Alter leave for Okita's Red Line.

Ritsuka and Okita Alter arrive at Okita's Red Line, where they were expected. Okita prepares to fight, stating she and the Okita Ritsuka knew are essentially different people. Okita Alter asks her if she is her, but Okita is unsure since she never wielded a large sword. She and Okita Alter then begin their duel.

Meanwhile at Nobunaga's Red Line, Ryoma and Oryou arrive after breaking through Nobunaga's forces. Nobunaga accuses him of abandoing the war, but Oryou reveals she already killed the official Rider. Ryoma reveals he is only in Tokyo to save the world. Nobunaga realizes he was sent by the Counter Force, and she is delighted at finally be the World's enemy. Ryoma then activates Like a Soaring Dragon, and begins his fight with her.

While continuing her duel with Okita, Okita Alter sees flashes of her past. It is revealed that her caretaker offered her to the World to save her from her terminal illness as a child, and in exchange, she became a Counter Guardian. Now having regained her memories, Okita Alter's swordsmanship drastically improves. Okita reveals her mana is constantly replenished in her Red Line, and the Grail's blessing doesn't allow her illness to affect her. She then puts on the Coat of Oaths, having decided to fight Okita Alter at full strength. After Okita is defeated, Ritsuka realizes she was trying to train Okita Alter during their duel, though she denies it. She then gives Okita Alter the Coat of Oaths, and tells her to protect Ritsuka like she failed to protect her own. After she disappears, Okita Alter recalls her purpose. She tells Ritsuka that they need to hurry as the end is coming.

After killing Oryou, Nobunaga declares she will destroy the world, and march onto the next. After Ryoma seemingly dies, Omani arrives. Nobunaga realizes he is Caster, and he introduces himself as. Nobunaga prepares to kill him when he removes his sunglasses.She instantly recognizes him, and becomes panically confused at the situation when she becomes paralyzed. Tenkai reveals all of Tokyo is his Red Line, and as the Grail War repeats itself, the mana produced goes to him. He has waited and planned for this moment for 300 years when the true Nobunaga shall returns. After his assistant takes Nobunaga away, Tenkai declares that with the Grail, Nobunaga's Saint Graph, and the Heroic Spirits in the city, it is time for his cause to manifest itself.

Returning to the detective agency, Ritsuka and Okita Alter are met by Nobukatsu. He begins to argue with himself when it's revealed he is sharing his Saint Graph with Nobunaga. She explains she was forcefully summoned into the Singularity by the Grail to be used as a puppet. However before her Saint Graph fully materialized, she cut herself off and escaped to somewhere. While normally impossible, she noticed Nobukatsu's Saint Graph got recorded somehow thanks to their previous encounter. She then took her chances to borrow his Saint Graph. Nobukatsu explains he is too weak of a Heroic Spirit to be summoned properly, but he is able to be thanks to Nobunaga's help. Da Vinci then reveals the Singularity was created to assemble Servants to forge a Saint Graph of a higher purity. Nobunaga compares it to a, and states such a ritual requires a Grail War where a massive number of Servants participate. Da Vinci reveals the Grail War has already been repeated many times before. Ryoma then returns and reveals it was thanks to Nobukatsu that was able to. Oryou is also survived since she is essentially Ryoma's Noble Phantasm. The group decide to stop Tenkai's plan when Izou decides to join. He asks if Tenkai has been located, but Nobunaga says his exact coordinates couldn't be pinpointed. The group then leave to locate Tenkai.

The group invade the Magus Facility where they were confronted by a numerous Heroic Spirit Soldiers. Ryoma explains they are basically artificial magic soldier created from recycled Saint Graphs. He, Oryou, and Izou stay to hold them, while the others proceed on ahead. Ritsuka, Okita Alter, and Nobunaga enter the chamber where Tenkai, whose revealed to be Akechi Mitsuhide, is. He declares the awakening of the true Nobunga is near. Nobunaga demands he return her body. Akechi responds by ordering Heroic Spirit Soldiers to kill the group. Meanwhile, Ryoma, Oryou, and Izou are exhausted and injured after fighting some many Heroic Spirit Soldiers. Just when they about to be killed, Hijikata arrives like Ryoma expected.

Meanwhile in the chamber, Okita Alter finishes killing a number of soldiers. She reveals her class is Alter Ego to Akechi's disbelief. He orders more soldiers to execute the group when Hijikata suddenly bursts in, followed by Ryoma and Oryou. Ryoma reveals he entered a ceasefire with Hijikata when he fought him earlier by mentioning Okita. As Hijikata kills his soldiers, Akechi is stabbed through the back by Izou. Nobunaga uses this chance to take back her body. After seeing Nobunaga won't accept his vision of an ideal world, Akech decides to become the true Nobunaga. He then uses the Grail, and black mud pours on him to transform him into a horrible monstrosity. Hijikata attacks him but its ineffective; Akechi declares himself Devil King of the Sixth Heaven. Ryoma questions how many Servants Akechi has absorbed, stating he's near the level of a Divine Spirit. The group try fighting him, but all of their attack are ineffective. Okita Alter tells them to do something about the Grail in his chest, then she'll finish it. Hijikata and Izou are attacking Akechi followed by Nobunaga Ryoma using Demon King of the Sixth Heaven and Like a Soaring Dragon together. As both Noble Phantasms assail Akechi, Izou removes the Grail from his chest. Ryoma and Oryou disappear, having expended the last of their magical energy. Okita Alter then uses the Grail to transports herself, Ritsuka, and Akechi into the sky of nothingness.

Inside the sky of nothingness, Okita Alter reveals she is a Counter Guardian. Akechi refuses to believe the Counter Force could interfere though since he turned Tokyo into a Singularity. Okita Alter asserts that in the sky of nothingness, nothing exists before and beyond it, and the same applies to him now. Okita Alter fights him after he question why no one, not even the World, accepts him. After defeating him, she makes him realize he was seeking forgiveness for killing Nobunaga in life. Returning to his regular self, Akechi accepts his as the truth, and disappears. Okita Alter then begins to disappear, and reveals she was summoned to stop Akechi. In exchange for saving her life, the World contracted her to be a Counter Guardian only once. Not wanting to disappear, she touch Ritsuka, and their memories begin flowing into her. She calls the memory of Chaldea proof that she lived, and disappears sincernely thanking Ritsuka.

Ritsuka returns to the still burning chamber. Mash states Imperial Tokyo is disintegrating, so Da Vinci starts the rayshift for Ritsuka. After they're rayshifted, it is revealed Ryoma and Oryou had faked their deaths, as Izou correctly surmised. They all then start having a friendly conversation as the chamber explodes.

In Ritsuka's room, Nobunaga finished telling Okita about what transpired and Okita Alter. Hijikata tells her that it was thanks to Okita Alter that her debt to the World has been paid. Okita Alter then suddenly enters the room and hugs Ritsuka. She believes she was able to return thanks to the power of love. Nobunaga assumes some interference occurred in Okita's Saint Graph. She also reveals she managed to summon Nobukatsu thanks to the minor alteration to her Saint Graph. Nobukatsu then appears, and decides to stay at Chaldea until he disappears again. Ryoma and Oryou also appear. He reveals they were blasted to somewhere near Chaldea somehow, and requests to join Chaldea. He wonders if his job isn't done yet since he didn't return to the Throne while Izou did. Meanwhile in the cafeteria, Lady Chacha schemes to resurrect the true imperial city.

Later, Nobunaga tells Ritsuka, Okita, and Okita Alter that she caught Chacha trying to use Chaldeas. Suddenly the alarm goes off, Da Vinci then alerts everyone that TRISMEGISTUS' simulation went out of control and opened a mysterious portal. She suspects someone abused the remnant data collected from the previous operation. Ritsuka, Okita, and Okita Alter prepare to rayshift into the portal. Nobunga infuses Okita Alter's katana with 3/4 of her mana to turn it into a god slaying demon sword infused with the power of Demon King of the Sixth Heaven. She dubs it the Sword of Purgatory. Afterwards, Ritsuka, Okita, and Okita Alter rayshift into the portal.

Inside her palace, Chacha thanks the elites of the Toyotomi army for assembling. She believes they answered the pamphlets she put up in Chaldea's cafeteria, though that isn't entirely true for most. She then declares all who participated in the previous event without inviting her will not be forgiven, and declares herself to now be Avenger Yodo. She orders her elites, the Seven Imperial Spears, to go forth, and gives them special soldiers crafted from Nobunaga's Saint Graph. Eventually her elites throughout Tokyo are defeated by the group followed by her.

Participants
Servants