- 1 Profile
- 2 Role
- 3 Abilities
- 4 Reception
- 5 References
Born into the prestigious Tohno family, Akiha lived a sheltered childhood under the strict supervision of her father Makihisa Tohno and was seldom allowed to go outside the mansion to play. She was also subconsciously afraid of her brother SHIKI, because of his strange and different behaviour. When Shiki Nanaya was adopted into the family, she initially disliked him because he had the same name as her brother. One day while she quietly waited for her tutor to arrive, Shiki took her hand, inviting her to play with him and SHIKI and Hisui, the other children at the mansion. Thanks to Shiki she was able to experience at least some semblance of the joys of childhood. Unfortunately, not soon afterward Shiki was near fatally wounded in an accident and was sent by Makihisa to live with the Arimas, relatives from another branch of the family. Akiha tried to visit Shiki at the Arima house several times early on, but pressure from her father and other relatives, in addition to Shiki's constant visits to the hospital, prevented their meeting. Contact was made all but impossible when Akiha was placed in a boarding school and she was forced to live on the campus. Akiha also states that she sent Shiki many letters, but because he was ordered by Makihisa to never speak to Akiha again, he never replied.
Sometime later, Akiha and Hisui learned that Makihisa raped Kohaku daily in order to maintain his demon blood. Akiha freed Kohaku from Makihisa, and allowed her to live as a normal maid. Upon the death of Makihisa, Akiha became the head of the Tohno household and, ignoring protests from the remaining relatives, called Shiki back to live at the family mansion with her.
Akiha has long black hair (that turns red in her Crimson Red Vermillion form) decorated with a white hairband. During school, she wears the standard Asagami uniform, even when she later transfers to Shiki's school. Her casual clothes consist of a white shirt with a red ribbon on the necktie and a long red skirt with knee-high brown lace-up boots underneath (which oddly are replaced with socks and slip-on formal shoes in her Melty Blood sprites).
Akiha is very protective of her brother. She is always intent on knowing what he does with his day, and is extremely suspicious of what he does at night. She gets incredibly jealous when he is around other girls. The constant supervision by his little sister sometimes bears hard on Shiki, but she only watches over him because she worries so much about him. Despite her general peevishness, she really is a sweet girl at heart. She plays the violin in her spare time.
Her father remarked in his journal that Akiha's Tohno blood was of the weaker sort and she could live as a normal human if she wished it. But that changed when Shiki's life was threatened in the "accident" from eight years earlier. She was outside playing with Shiki, her adopted brother, and her real brother, also named SHIKI. But the Tohno blood was much stronger in her real brother and he inverted to his non-human form. In this uncontrollable state, he lost control of himself and attempted to attack Akiha. Shiki jumped in the way to protect her and took the full force of the attack. Shiki died protecting Akiha, but Akiha used powers granted to her by her non-human blood to give him half of her life, allowing him to survive.
After the incident, her true brother SHIKI was locked away so that he could never again hurt someone and Akiha severed all ties with him and has since said that Shiki, her adopted brother, is the only person she will ever call her brother. Due to this accident, she needs twice the amount of heat of an average person because she is supporting both her own life and Shiki's. To make up for her increased demand, she must absorb heat from others. She can take this heat in through various means, even by simply absorbing their body heat through contact, but the most efficient method is by drinking fresh blood (as seen when she sucks Kohaku's blood in a scene from the game). Because of the strain on her body, this causes, she often experiences attacks of intense pain that can last from a few minutes to several hours. But Akiha bears them bravely, knowing that it is all for the sake of her beloved brother.
Akiha is also a rather judgemental person, having a tendency to hate people very quickly before she's ever really gotten a chance to know them; she instantly takes a disliking to both Arcueid and Ciel, Ciel due to being a member of an organization who opposes non-humans like herself and Arcueid because of how whimsical she is and how close she is to Shiki. She is also very self-conscious about her flat chest and it later causes lots of running gags in later sequels like Kagetsu Tohya.
Though she tries to conceal it, Akiha called her brother back because she truly loves him and wanted to be near him no matter how much it might alienate her from the rest of the family. She is incredibly shy about her feelings, even acting in complete contradiction to them on occasion. In spite of this, to her, Shiki is the most important person in the world.
« It has been a long time, Nii-san. »
|(Akiha greeting Shiki for the first time in years - Akiha's route, Day 1)|
Because the events of Arcueid (and Ciel) keep Shiki away from the Tohno mansion, Akiha has a secondary role and she remains as Shiki's stoic yet caring sister, who wants to keep the awful truths about their past from Shiki. She scolds him over everything, from his manners to coming back home at late hours. However, Kohaku (who is very close to Akiha) reveals to Shiki that despite her stoic demeanor, Akiha is pleased by Shiki's return. Nearly the end of the route, she reveals to Shiki that he was adopted.
Similar to Arcueid's route, she plays a supportive route and does not seem to like Ciel.
« If I didn't tell you... if we stayed brother and sister... we could stay together. Since I'm not human, since I'm too different from you, we can't stay together......!? »
|(Akiha, after telling Shiki the truth about his past - Akiha's route, Day 11)|
Shiki returns to the Tohno house after years. He fondly remembers the times he spent with his sister Akiha. He also feels guilty because of the strict upbringing she received after he had to left the Tohno house. Unfortunately for Shiki, his reunion with Akiha is not exactly as he had hoped it to be. She is cold and distant to him, immediately demanding that he adopt a lifestyle befitting of the eldest son of the Tohno family. Akiha scolds Shiki over everything, which causes him to believe that she might bear a significant grudge over his absence the last eight years. When Shiki goes to school, he realizes that his classmate Satsuki is gone. Later it is revealed that she was turned into a vampire by SHIKI.
When Shiki, who had just crossed ways with Satsuki, returns home he is scolded by Akiha but she later treats his wounds. The next day, Shiki decides to confront the vampire Satsuki after he promises to Akiha that he would come back home safe. Satsuki tries to turn him into a vampire to be with her forever, and it that moment Shiki realizes his feelings for Akiha and their promise. Motivated by it, he kills Satsuki, although regretfully. When he returns home, he notices that Akiha was waiting for him the whole time and chastises him for returning wounded.
Akiha decides to spend more time with Shiki by joining into the same school at him. Like Arcueid, she does not like Ciel. It is revealed through the route that Akiha often struggles to maintain control over her Tohno blood and resisting her Inversion Impulse, which she has difficulty with due to her also maintaining Shiki's life, to the point she also had to drink Kohaku’s blood. When Ciel vanishes, Akiha reveals to Shiki that she always knew that Ciel was different and she was unaffected by her hypnosis. Due to the recent killings in the city recently, Shiki believes that Akiha might be the vampire who did it and goes to the Tohno house. When he arrives, he sees Akiha unconscious and that SHIKI is there. He tells him that he went to take Akiha "back with him" and reveals to Shiki all the truths of their childhood. However, Akiha regains consciousness and protects Shiki. The two have a confrontation about Shiki, only for Akiha to say in his face that Shiki is her brother now and that she does not consider SHIKI as her brother anymore. SHIKI is angered of this revelation and aims to kill him, but Akiha protects Shiki and takes the attack. This causes Shiki to have a homicidal impulse and cut SHIKI’s lines.
After that, Akiha and Shiki talk in her room, where she tells him that in fact, Shiki was adopted after SHIKI killed him and due to it, their minds are connected and he took a part of his life (she also tells him that she believes that one of the causes of their connection might be related to the fact Shiki and SHIKI used to be best friends when younger). Then, she starts having spasms and her hair turns red. Akiha confesses to Shiki that she was aware from the beginning that he is not her real brother, but she felt that it was the only way for her to be with him. However, Shiki reassures her that he loves her as a sister and a woman and they kiss and have sex together. After this, SHIKI is filled with jealousy and reveals to Shiki that Akiha has been maintaining his life since he died eight years ago. Akiha is later kidnapped by SHIKI.
Later, when Shiki comes to the abandoned room in order to confront SHIKI and save Akiha, he discovers that SHIKI turned her into a mindless, blood-sucking creature. Both fight and Shiki manages to debilitate him. However, at the last moment, Shiki hesitates to kill him so SHIKI uses the last of his energy to return to the abandoned house and see Akiha. Surprisingly, Akiha, now a mindless monster, kills SHIKI by ripping his heart off and runs away. He is left with the choice to kill her and save her from her suffering or to let her live in her current state.
In Akiha's Normal Ending, Shiki decides to allow her to live on as the demon that she currently is (because Shiki cannot bring himself to kill her). This results in Akiha's Normal Ending, where Shiki maintains Akiha at the abandoned room and tries to contain her bloodlust by himself, by routinely letting her painfully bite him and suck his blood out of the wound, all the while hoping that someday she will find herself again.
If Shiki decides to kill her to end her suffering (which she requested for him to do if she ever became like this) it gives no special ending and is considered a bad end.
In Akiha's True Ending, he decides to kill himself instead (so that she will regain the life energy she gave Shiki when he died eight years ago, and then will be restored to her full strength so she can more easily resist her Tohno blood impulses and restore her mind). With this,
Akiha's True Ending is obtained, in which Akiha regains her sanity and when she wakes up, she realizes what Shiki did. Akiha is able to live a normal life and returns to her old school. One day, she goes to the place where he died and sees Shiki's Nanatsu Yoru knife. Despite the fact that Shiki should be dead, Akiha touches the knife and senses deep inside her that there still seems to be a faint heartbeat that is not her own. She recognizes this as a sign that Shiki is still somehow alive somewhere, and that as long as she feels it, she has hope, and declares that she will faithfully await his return.
In "A Story for the Evening", a 'sequel' scenario to Akiha's True Ending from Kagetsu Tohya, at the end of the scenario Akiha receives a letter from Ciel that reveals that Shiki did in fact survive, and that he had been under her care that whole time until he was fully recovered. Shiki's treatment being completed, he waits for Akiha in the mansion for her return from the boarding school.
« I'm sorry. I...I've deceived you all this time. I've kept secrets about many, so many things. »
|(Akiha in her last moments, after being fatally wounded by SHIKI - Hisui's route, Day 12)|
It is revealed that she always knew that Kohaku was planning her revenge on the Tohno family, but felt that since her family has wronged Kohaku to an incredible degree she ought to be at least given a chance.
In Hisui's True Ending, she dies while protecting Kohaku with her body from SHIKI. Despite Kohaku expected for Akiha to sacrifice herself and was rather willing to let it happen just for the sake of her revenge, her death causes a great impact on Kohaku, as she was her close friend. Before committing suicide, Kohaku realizes she keeps bringing tea to Akiha's room, even after she has died.
In Hisui's Good Ending, she is only injured in her arm by SHIKI and she is later treated and survives.
« ...Don't get me wrong, Nii-san. I do not call you Nii-san for the sake of society. Do you not remember? Even before you were killed by SHIKI, I called you Nii-san. It had nothing to do with you being adopted. I knew from the very beginning you were not my true brother. And you accepted that too. So...no matter what you think, you are Shiki Tohno. So please stay here in this mansion. »
|(Akiha to Shiki - Kohaku's route, Day 7)|
Akiha successfully tracks down and kills SHIKI before Shiki even starts having dreams visions of him, and is happy that she was able to protect Shiki from having to face all the pains from their past. However, due to SHIKI's ability of immortality and the nature of Akiha's powers, SHIKI is able to give Akiha one final curse before he dies. He transfers the burden of his madness caused by the inversion impulse of his Tohno blood over to her when Akiha absorbs his energy to kill him. After this, Akiha begins to slowly succumb to the Tohno blood, despite her originally being quite capable of controlling it. She synchronizes with Kohaku in an attempt to suppress this, but it is not enough, since she now has SHIKI's bloodlust itself. Even though she does not kill them, she begins hunting for victims on the streets at night in SHIKI's place because she cannot control herself.
This madness also affects her mentality, and she soon becomes single-mindedly obsessed with Shiki, to the point where she threatens to take back the life she gave him if he does not declare that he loves her. Shiki admits that he came back to the Tohno Mansion to be with her again, but he also came back to fulfill a promise he made to Kohaku, who is the one he truly is in love with (at least in this route). He only loves her as a sister, and Akiha has deteriorated to the point where she decides if she cannot have him, she will not let anyone else have him.
In Kohaku's True Ending, Shiki synchronizes with Kohaku to gain strength, and engages Akiha in a climactic battle. But just as he is about to kill her, he finds himself unable to, since no matter what, she is still his sister (if he kills her, it is considered a Bad Ending and Kohaku also dies). Shiki's display of love for Akiha, combined with Kohaku saying she forgives the Tohno family, is able to move her enough that she regains control over herself. She recovers and is able to live a normal life, albeit still having to deal with the desire to drink blood, which she quenches by drinking blood packs ordinarily used for transfusions.
In the manga version of Tsukihime (which follows the Arcueid's route), she has the same protective role towards Shiki. Ciel tests whether Akiha has it in her to be a murderer by threatening her and her brother and then fighting her to the death. What Akiha doesn't know is that Ciel cannot be (permanently) killed/injured, so Ciel is free to test Akiha's power with impunity and make Akiha stab her in the face. Akiha's horror showed that she was not the killer.
The childhood memories are more emphasized in the manga, showing that SHIKI was the one who suggested Shiki to invite Akiha to play and that she was jealous of how close the two Shikis were. However, there is one slight difference in the way Shiki remembers his past: after he recalls how there was another boy in his childhood and how he had killed him, SHIKI appears and attacks him. Shiki is saved by Akiha and Kohaku and the two siblings have a confrontation about Shiki. After Akiha tells him that she does not acknowledge him as her brother anymore and that Shiki is her brother now, an enraged SHIKI tries to attack her but she is protected by Ciel, who explains that SHIKI is a vampire, but Akiha is unable to understand.
Near the end, after Roa takes full control of SHIKI's body and Shiki is gravely injured, Akiha uses her life once again to heal him up. She then explains the truth about his adoption and his connection to SHIKI before Shiki leaves to save Arcueid and defeat Roa.
She remains as a supportive character, but she is the protagonist of the side story A Story for the Evening, which is the continuation of Akiha's True Ending in Tsukihime. Tsukasa Shijyou, a classmate of Akiha, placed a curse on her due to an urban legend, but is afraid she will find out, and attempts to kill Akiha by knocking her off two stories from the roof. Akiha survives due to her super-human abilities and Tsukasa comes in the night to kill her with a knife, but Akiha yet again survives and knocks out Tsukasa. After resolving the mystery, Akiha receives a letter from Ciel, that informs that she saved Shiki from death and that he would return by the end of the year.
Akiha has two versions of herself in Melty Blood and in the storyline of the game. The first is her normal state, where she decides by herself solve the mysterious problems caused by TATARI to protect her brother Shiki. She also ends up meeting Sion Eltnam Atlasia, forming a friendship of respect. Their relationship is a lot better than that of Akiha and Arcueid or Ciel, because she believes that Sion wants nothing more with Shiki than just his friendship to help solve the case of the return of the vampire serial killer a year ago.
The second state is called Akiha Vermilion (紅赤朱秋葉, Kurenai Sekishu Akiha?, Crimson Red Vermilion Akiha, ou 赤主秋葉, Sekishu Akiha?, Red Lady Akiha), based on her form of Crimson Red Vermillion. Akiha Vermilion is what becomes of Akiha when she has given into her demonic blood of Tohno family. This version of her is a little more dark and sinister, lacking most of the refined air of normal Akiha, and in its place is a subtle, yet malevolent violent streak in her personality and actions. She appears in this form in Melty Blood as a heroine in some of the routes of the game (especially in relation to the Tohno family rotes) and another as a manifestation of TATARI materialized by Night of Wallachia, through the rumors made by people about a mysterious Japanese vampire with long long hair, wandering and attacking people at night and combined the fears that Shiki Tohno always have of his sister when she is in this state. Shiki defeated Wallachia at the end of these routes when he was using that form of Akiha.
In the sequels of Melty Blood, Akiha always appears in these two forms as separate characters to solve the cases that would be caused by TATARIs caused by White Len in Melty Blood Re-ACT and Dust of Osiris in Melty Blood Actress Again. In Melty Blood Act Cadenza, Akiha in her Crimson Red Vermilion form, influenced by Kohaku, decides to solve the strange disorder of Misaki Town and enjoys eliminating the competition for the affection of her brother Shiki.
In Melty Blood Actress Again, in her form of Crimson Red Vermilion, she ends up discovering the personal enemies of the Tohno family and of Shiki, Kouma Kishima and Michael Roa Valdamjong (acting as SHIKI Tohno in part of the conversation in her storymode) in his way, with they brought for TATARI of Dust of Osiris. She defeats the two to protect her brother from suffering to face them again.
« Geez! I know we're here to play, but you're still the eldest son of the Tohno family! »
|(Akiha at the beach with Shiki and the girls - Carnival Phantasm, Episode 2)|
Akiha has a number of roles in Carnival Phantasm as one of the heroines of Tsukihime. Her tsundere personality is comically exaggerated and she is very conscious about her flat chest, becoming very violent if someone points it out. If she is angered, she becomes Vermillion Akiha, with Shiki as her usual target. In the Phantasmoon segment, she appears as the main villain, an evil youkai.
The Caging Hair (檻髪, Origami?) is the ability of Akiha; it is a cursed field of plundering that is effective in the range of her field of vision. Being a half-demon, she can "plunder" the heat (lifeforce) from a living creature she can see, but the maximum output relies on time (on how long she keeps plundering heat). At the same time is it a double-edged sword as she can plunder someones entire concept with it as well. The ability of interfering with the outside world is rare, even within the Tohno family. On the other hand, is she also able to share her own lifeforce with others and can so animate a dead animal/human or non-living object and use it as a servant.
Akiha can start up the plundering once she has confirmed her target, and people who have a spiritual perception will see it as red strands (her hair's true shade) wrapping around the target and charring. In addition to becoming red, her long hair can extend and become a menacing weapon. She is able to control its movements and use it to absorb heat directly from anything it comes into contact with. The drawing out of the heat produces a powerful burning sensation on the surface of the object, causing some viewers of her abilities to believe that she was simply setting things on fire. It does not actually burn the target, as it doesn't affect the target's clothes and stops burning as soon as Akiha stops plundering lifeforce from the target. At its maximum , the red strands cover the target as well as the entire area the target is in, making it impossible to escape - hence the name, caging hair. The hair, in this form, is incredibly fast and can strike an object as quickly as Akiha can look at it, but Akiha herself cannot see them, as she has no special mystic eyes.
It is an absolute offensive ability against a normal person who doesn't have any spiritual defense, but it won't be any more of a hindrance than a large spider web to someone with a spiritual status on a whole different league such as Arcueid Brunestud, or a Heroic Spirit. Although, with support, she could use it as shackles to restrain beings of that level.
The power of a Crimson Red Vermillion can be seen through the Arc-Drives of Akiha and Kouma Kishima in Melty Blood. Kouma is closer to the state of Crimson Red Vermillion than Akiha, but she is fundamentally superior in terms of functioning in the state of Crimson Red Vermillion. Normal individuals lose their sanity while progressing towards the status of Crimson Red Vermillion, but Akiha has managed to still have enough reserve to hold onto her sanity due to her superior quality as a Half Blood. Absorbing Roa's soul after killing SHIKI in Kohaku's route increases her power and gives her better control over her Tohno blood, allowing her to hide her red hair color. It is initially hard to control, causing her to go on her obsessive rampage over Shiki, but she gains control over it afterward. Its strength weakened upon transferring to her, so she is only made more strong-willed and honest from its influence.
 Tsukihime Dokuhon PlusPeriod - TSUKIHIME Dictionary: Tohno Akiha [Person's name], p.185
Akiha Tohno [Person's name]
One of the heroines in Tsukihime. Shiki's younger sister, and the Tohno family's heir.
She has long black hair and a dignified posture, firm speech, and an unendearing personality. On top of that, her love of strict discipline can make her somewhat hard to get along with.
Perhaps it's because she doesn't think much of the way Shiki lived doing whatever he pleased for eight years, but she lashes out at him every chance she gets. Though she is basically straightforward and honest at her core, she is also unyielding and hates losing, so her true personality rarely gets a chance to shine.
She was one of the people involved in the accident eight years ago, after which her dormant Tohno blood was awakened. Though she would have been able to suppress it if she only had to worry about herself, she was carrying the burden of two people. As a result, she started being attacked by seizures nearly every night, and at Kohaku's suggestion began drinking blood to maintain her body.
…Of course, it was all just a scheme to push Akiha closer to her Tohno nature. Probably, even Akiha herself was aware of it on some level.
In one of the routes, she ended up inverting and demonstrating her power to its fullest extent. That dreadful form, with its fluttering vermilion hair, is probably capable of exceeding even a rampaging Arcueid.
Long ago, in the Tohno's country, there lived a female oni named Momiji. Though she is not their ancestor, maybe you could consider her the origin of Akiha?
Incidentally, Akiha is the character with the greatest number of individual sprites. It actually made the art director break down in tears. Not only were there uniform sprites and casual sprites, but sprites for Akiha when she was inverted as well.
Also, by some strange twist of fate, her roommate at school actually had the last name "Tsukihime".
She was the only heroine in Tsukihime that didn't get a happy ending, which apparently made a lot of fans mad. We got a ton of hate mail demanding that we do something about it, hahaha. I guess it worked, though, since we ended up writing a sequel to Akiha's ending for Kagetsu Tohya.
She is the student council vice president at the Asagami Academy for Girls, and seems to be quite popular.
…Of course, that popularity stems from equal parts reverence and terror.
In Kagetsu Tohya, the power relationship between her and Kohaku began to change, and in Melty Blood she was the victim of Kohaku's cheerful treachery. Also, though the Akiha in Melty Blood is pretty… energetic, she's normally a little more graceful than that.
She totally lacks the pride and thin skin characteristic of the super-rich, but her sense for how to use money is still grossly out of sync with normal people's.
When she told Sion to "rest a bit", in Akiha's head "a bit" meant either until Sion herself was sick of it, or until she was dead. It seems she's the type of person who's cold to strangers, but excessively soft toward those who have earned her favor. Ah, so that's why you let Kohaku toy with you as she pleases, Lady Akiha!
- Lunar Legend Tsukihime Chapter 23
- Lunar Legend Tsukihime Chapter 24
- Lunar Legend Tsukihime Chapter 25
- Lunar Legend Tsukihime Chapter 46
- Lunar Legend Tsukihime Chapter 49
- Lunar Legend Tsukihime Chapter 62
- Lunar Legend Tsukihime Chapter 63
 Tsukihime Dokuhon PlusPeriod - TSUKIHIME Dictionary: Caging Hair [Unusual talent], p.176-177
Caging Hair [Unusual talent]
Caging Hair. It's the name of the tenth day of the Kohaku route, but here it's referring to the name of Akiha's ability.
Akiha is a demon hybrid that "plunders" the heat of any living being that she is able to visually confirm, and Origami is the name for the maximum output state of this ability. Though the plundering is based on sight, if somebody with spiritual vision were to observe it, they would see it as something similar to red threads twining around and consuming the target in a fiery aura. And, at their maximum output, these threads are capable of covering not just the target, but the entire environment the target is in, making escape impossible – thus the name Origami, or "Caging Hair". During the last day of the Kohaku route, the reason Shiki couldn't escape from the school building was because the school building itself had been totally covered by Akiha's Origami.
Against normal people with no spiritual defenses, this is an absolute method of attack, but against somebody like Arcueid whose spiritual rank is on a whole other level, it would merely be a hindrance similar to the world being filled with spider webs. Though, with backup from a sympath it might be able to actually tie her down.
In Melty Blood, it became both Akiha and Vermilion Akiha's Arc Drive, under the name "Red Lord Origami".
Also, this is just a digression, but the martial arts practiced by the Tohno family are divided into "Blazing Rendition" techniques usable by everybody, and "Red Lord" techniques permitted only to the family head.
These are in turn surpassed by the "Crimson Lord" techniques, which are a taboo even among the taboo.
 Melty Blood Act Cadenza - Dictionary: Red Lord Origami [Technique name]
Red Lord Origami [Technique name]
Tohno Akiha's Arc Drive.
For just a moment, she fully unleashes her power and "plunders" the opponent. The reason her hair turns red is because her true nature is shining through.
At one point in Tsukihime, the schoolhouse was totally covered in red threads, making escape impossible for the prey trapped within. Without a doubt, that was Origami. The outlandish spectacle from that time makes its reappearance during Tohno Akiha's Last Arc.
 Tsukihime Dokuhon PlusPeriod - TSUKIHIME Dictionary: Crimson Red Vermilion [Term], p.178
Crimson Red Vermilion [Term]
The name for when those with inhuman heritage have drawn out their sleeping blood to the maximum possible extent. Once they reach this state, they are wreathed in a mirage-like haze and can never return to being human.
The name Crimson Red Vermilion is unique to the families ruled over by the Tohno household. Elsewhere, it is known as Ancestral Return.
As one with particularly tainted blood, the possibility that Akiha will become a Crimson Red Vermilion is high.
In Tsukihime, when her hair turned deep crimson, she was on the verge of this, though somehow she managed to bring her human and oni blood under control. Of course, rather than returning to how she was before, it's more accurate to say she switched to her "human" self while remaining close to the state Crimson Red Vermilion.
 Melty Blood Act Cadenza PS2 Manual - Dictionary: Vermillion Akiha [Person's name], p.053
Akiha Vermillion [Person's name]
Akiha in a state close to Crimson Red Vermilion.
Through sheer willpower alone, she is able to control her rampage and avoid fully becoming a Crimson Red Vermilion.
Or rather, for Akiha this form is actually what she looks like when she's conserving her strength, and her normal form is the result of her actively using her power to suppress her oni blood. It's quite similar to the situation with Arcueid and her vampiric impulse.
Properly speaking, becoming a Crimson Red Vermilion means completely losing your ability to reason, but it seems even in this state Akiha still has some sanity left.
This, too, is probably by virtue of her high aptitude for it.
- Ryukishi07 blog post