- "Demand it! Ask for it! Seek out more power!!"
- —Mahiru-no-Yo to Guren[src]
Mahiru-no-Yo (真昼ノ夜 Mahiru-no-Yoru?, lit. "Midday's Night") is a possession-type demon of the Black Demon Series. She is Guren Ichinose's former human lover, Mahiru Hīragi who sealed herself within a sword and became Guren's Cursed Gear.
Mahiru-no-Yo appears exactly as Mahiru with the exception of having fangs and red eyes due to having been a vampire when turned. She is the only demon who does not have pointed ears or horns unlike the others. She still wears the female First Shibuya High School uniform, a sailor fuku.
In her sword form, she appears as a black katana with a glowing crimson, red streak that is outlined down in the middle portion of the blade.
Merged with the demon in his sword to become Mahiru-no-Yo, being a possession-type demon suggests she is particularly violent. She helps Guren grow into a namanari and possesses him as needed to make Guren's demonic side take control; however, Mahiru-no-Yo's balanced demon and human personalities she had as a vampire remain as she does not appear to be as twisted as when she used to be as a namanari such as being able to make calm and rational decisions. She also retains her love for Guren and Shinoa, though twisted as she seeks to turn the former into a demon and hoping for the latter's love will awaken her demon to so that she can become stronger. Having said that, Mahiru-no-Yo shows concern for them, particularly Shinoa, whenever Shikama Dōji is involved as when she told Shinoa to hang in there to save her from the possession. Mahiru-no-Yo also showed that she does have a softer side towards Guren, taking time to comfort Guren genuinely when he was about to become a demon over his furious guilt of causing the Catastrophe, even taking responsibility for it along with him, and showing somberness as Guren notes on his regret over being unable to save her, and even seems to show some concern towards Guren's Squad, as she silences Noya when he tempts Guren to reveal the truth, which will kill them, and tries to give Shinya a reassuring smile.
Mahiru-no-Yo was actually Guren's previous demon, Noya. When Guren threw away Noya, Mahiru picked up the weapon and stabbed herself with it in the heart where she merged with it which was what Mahiru had planned all along. Noya was unable to stop the curse from spreading and eventually Mahiru was sealed/fused by Noya thus transforming her into Mahiru-no-Yo. She became the demon within his Cursed Gear and part of the Black Demon Series.
Events of 2020Edit
Second Shibuya High School Arc Edit
When a vampire escapes the school grounds, Guren uses Mahiru-no-Yo to slay it of which the power caused the vampire to disintegrate. Later when Kimizuki arrives in Guren's office and asks him if he can receive a demon weapon, Guren provides a demonstration of cursed gears power by showing him his demon aura as it fills his office.
Later, Guren arrives at the classroom and unleashes Mahiru-no-Yo's demonic aura that sends most of the class tumbling to the floor, many of whom go unconscious without the willpower to withstand it. Shinoa manages to remain standing because of her immunity to all demons, and Yoichi is completely unaffected by the attack to the point where he does not even feel it. Yu and Kimizuki manage to withstand the demonic aura, though they tremble.
Shinjuku Arc Edit
Post-Shinjuku Arc Edit
Following a conversation with Shinoa, Guren meets with Mahiru-no-Yo in his mind. She wants him to seek more power. When Guren addresses her, Mahiru-no-Yo says she's glad that he came as she wanted to meet with him.
Guren challenges Yu to a fight to test him for the next step of mastering his demon, and in the fight, Guren orders Mahiru-no-Yo to possess him and overwhelms him.
Following their small talk, Guren reveals her form during a fight with Yu. After hearing Guren summon his demon by calling out her name, Shinoa holds her scythe at Guren's neck. She reveals that her weapon specializes in long-range combat and consequently stands no chance against a melee fighter like Guren at that range. Guren calmly says he would let Shinoa kill him. Shinoa asks him if that is his way to atone for killing her sister, unbeknownst to her that Mahiru stabbed herself by Guren's previous demon. Shinoa asks if she is in his sword since she heard him call her name. Guren says that Mahiru is already gone since she turned into a demon and saved the world by completing Cursed Gear.
Shinoa asks him if Mahiru is together with him inside his sword, stating that he is being possessed by her. Guren asks her if they ever got along. She explains that she was not close with her sister because Hīragis are raised without knowing familial love.
Shinoa asks if making use of Yu was one of Mahiru's orders and asks if her half-sister or the demon for lack of a better word inside his sword is ordering him. She then asks him to stop what he is doing if his goal does not benefit Yu.
Guren tells her that Mahiru is dead and isn't coming back. He says that the demon inside his sword is under control so he isn't being possessed by her. But Shinoa doesn't believe him.
Nagoya Arc Edit
At the beginning of Nagoya, Mahiru-no-Yo appears and whispers to Guren in order to make sure he follows her rather than Lieutenant General Kureto Hīragi.
Mahiru-no-Yo later forms again, and possesses Guren and kills the noble, beating him. She uses Guren's body to point a sword at Krul Tepes and states that Krul will help her conduct an experiment on the Seraph of the End at Nagoya Airport.
At the Ebina rest stop Guren punishes Shinoa squad, in the fight against Yu Guren releases a powerful red whirlwind from his demon destroying the doors and knocking over Shinoa and Mitsuba. After the fight Shinoa charges at Guren only for her demon to get knocked off using Mahiru-no-Yo.
After defeating Mel Stefano, Guren moves to his next targets on his list Thirteenth Progenitor Crowley Eusford. Chess Belle and Horn Skuld. When Crowley was overpowering him he released Mahiru-no-Yo by in the ceiling by calling out it's name releasing dark crimson sparks. Guren eventually gets captured by the vampires after the fight with Crowley he was seen near Krul Tepes and a few of her soldiers. He was being beaten by a noble, the angered noble grabs Guren by the hair and raises up his face, when Guren spits on his face the vampire curses him and kicks him to the ground threatening to kill him.
At this point, Guren's personality begins to change as Mahiru-no-Yo possesses him and turned him into a namanari. With this power they easily behead the noble, with the sword appearing to have a will of it's own as it unsheathes itself. Guren's personality would change into more demonic and heartless though even in this state they could not defeat third progenitor Krul Tepes.
Guren soon arrives at the airport in Nagoya where the experiments are being held by Kureto. Guren raises up his sword, and chains wrap around his arm as the curse consumes him speaking the words to drink the blood of human sacrifices, demons, and the progenitor turning Mahiru-no-Yo from black to complete pure red color similar to first-class vampire weapons. Guren then slaughters both vampires and a humans confusing everyone except Kureto,
After Yu stops the demon Abaddon, Guren still possessed by Mahiru-no-Yo, tells Yu to do it and break their taboos. As Guren chases Yu, Shinya stops him and asks him about betraying so many of his men before realizing Guren has been possessed.
Post-Nagoya Arc Edit
After three months time skip Guren and Kureto can be seen walking and fighting together side by side against the vampires with their demon weapons. While so, both men commanded their respective demons to attack the enemies before them On his way back to Shinjuku, Guren injects the drug into his forearm while a soldier drives him. The drug suppresses his demon.
Osaka Arc Edit
While Guren is driving away with the team, he reminisces back to eight years ago, when he triggered the Apocalypse by reviving his friends for the next ten years in order to be with them. Mahiru-no-Yo then manifests, and warns Guren that if his team ever learned that they are actually dead, they'll turn to dust. Once Guren tells her to disappear, she goes to the roof where she is then confronted by Byakkomaru. He demands for Mahiru-no-Yo to identify herself as she's not a demon; in response, she inquires him on what he would do about it. Byakkomaru replies that he would do nothing, unless she harmed Shinya. Mahiru threatens to kill Shinya if he knows about her, and harshly silences Byakkomaru.
Guren tells her to leave, and Mahiru-no-Yo goes ahead of everyone to Osaka. She smells the scents of Shinoa and burning vampires which leads her to go investigate the latter scent. She appears right in front of an unsuspecting Ky Luc, before turning her attention to the burning crosses holding Ferid and Krul. Mahiru-no-Yo taunts a suffering Ferid, which caused him to notice her.
Despite Ky Luc being unable to see Mahiru-no-Yo, he gets an unsettling feeling, and tries slicing at it, but gives up. She then appears on the road that Guren and co are heading down. Upon seeing Mahiru-no-Yo waving to him, Guren tries unsuccessfully run her over. After arriving to Ferid's mansion, Guren summons her to knock out out the whole squad except for Shinya. She forms next to Guren, and comments that Byakkomaru is searching to kill to him. Guren says it's because she provoked him; as well as becoming annoyed with Mahiru-no-Yo before the fighting begins.
Seeing Guren and Shinya getting ready to battle, Mahiru says that this is the first time the two are fighting over her since high school. Guren denies this, and Mahiru-no-Yo continues by telling Guren she will sleep with whoever wins and claims it's his favorite scenario. Mahiru-no-Yo reappears after Guren's victory, watching over an unconscious Shinya before asking Guren why he brought his squad here; reminding him that they could be destroyed if they find out the truth. Though Guren doesn't answer her, Mahiru-no-Yo realizes that Guren is close to becoming a demon, thus he purposefully made his friends aware that he was hiding something to maintain his grip on his humanity. When Guren tells her to leave him alone, Mahiru-no-Yo reminds him that he has the power to banish her whenever he wants to.
She later manifests in front of Shinoa, and expresses joy over seeing her alive and well, but then wonders why Shinoa is unable to see her. . Mahiru-no-Yo says that Shinoa should exceed her as an experiment before realizing that her demon has not awakened. She goes on to say that love, more specifically sexual desire and lust, will corrupt Shinoa until she no longer cares about the world. She stared at the gathering squad and noticed that Shinoa has her eyes set on Yu.From him, Mahiru-no-Yo glances down to Shinoa, and sees that her younger half-sister is gazing at him. With that, Mahiru-no-Yo leaves telling Shinoa how much she is enjoying this.
Guren summons Mahiru-no-Yo to attack Ky Luc, and he recalls his uneasy feeling, having sensed her before.
Shibuya Arc Edit
After the talk between Kureto and Guren, Kureto decides to attack him and Shinya. Guren summons Mahiru-no-Yo and manages to defend himself. She notices that Kureto has a great surge of power when he drew Raimeiki and when Shinoa comments this is bad, she agrees. Mahiru-no-Yo sees Shikama Doji floating behind Kureto and warns Guren that Kureto is being possessed by some unbelievably powerful monster.
Later on, Guren notices Mahiru-no-Yo manifests next to Shinoa after hearing Shinoa talks about how Shikama Dōji may have possessed her. She listens to Shinoa talking about how she gave up her life for to protect her from Shikama Doji with any hope of a relationship with Guren and Shinoa teases Guren that it is because of her that Mahiru-no-Yo never got to be together with Guren despite their love. After hearing Guren saying that the past doesn't matter that the catastrophe destroyed the world and how the past is gone and won't be back also what they should focus on the present situation and what they can do now, Mahiru-no-Yo complements Guren about his speech. Mahiru-no-Yo later sits next to her sister still manifested whom Shinoa can't see her.When Guren and Kureto discuss how Shikama Doji went after Shinoa instead of Kureto since she is Mahiru's sister, Mahiru-no-Yo manifests and she listens to their conversation silently.  She hovers nearby to Shinya and glances to frown at him since Guren knows he cannot let the dead realize they have been brought back to life or they will return to dust. Kureto suspects the monster went after Mahiru first and she makes no comment on that, or on speculation on why she approached Saito. However when Kureto asks Guren by whom or what is he possessed by and who is imprisoning him, Mahiru answers that the question is easy, that Guren is prisoner to love and friendship while embracing Shinya by the neck.
After the escape of Shinoa due to Saito's arrival, she manifests and tells Guren it won't be long before Saito and Krul arrive and it's time to betray everyone just as both of them planned, which Guren agree's on.
Mahiru-no-Yo continues urging Guren on betraying everyone even more assuring him it will only take a moment. They encourage Guren to let himself change to become the other Guren.
Mahiru-no-Yo contently asks Guren once more if he is ready to turn into a demon, and tells him she would give lots of encouragement when Guren alludes to declining. Saying that he is silly, Mahiru-no-Yo asks what he is going on about, failing is easier than succeeding since he could escape his responsibilities. Hugging him, they call Guren a crybaby and asks if he is scared. With the answer being in the affirmative, they ask since when. A flashback occurs when as Mahiru she first met Guren and was taken away from him.
Appearing concerned as they listen to Guren speak about how she had no one there to help her, and so no choice but to become a demon, Mahiru-no-Yo states that is not his fault. The catastrophe was going to happen, it was planned that way and if Guren had not done it, someone else would have.
Trying to alleviate his guilt, Mahiru-no-Yo hugs Guren tightly and tells him it is both their fault, and now Guren is trying to take responsibility for it. They assure him it is okay, and not to worry, he will do it right and succeed. Seeing the chains emerge from Guren, she supports this telling him he is doing well and to keep it up, they will keep him safe. Mahiru-no-Yo intends to take half the demon into them, and will not allow Guren to go berserk
Noticing that Shinya and his squad have found Guren, she resumes persuading Guren to close his eyes and dive inside for Shinya, to save all of them. After some chains are shot, Mahiru-no-Yo makes eye contact with Shinya who can see them and is also perplexed at this fact. Mahiru-no-Yo reasons that it is because Guren is holding half the demon now. With Shinya's rifle aimed at them, they are demanded to say what is being done to Guren, but that is a secret. Holding Guren, Mahiru-no-Yo laughs off Shinya's declaration to kill them, telling him he does not have the power to do that. In response to Byakkomaru being called upon, Mahiru-no-Yo verbally activates the chains. With other squad members now able to perceive them, Mahiru-no-Yo has had enough of this nonsense and orders Guren to close his eyes. Once inside his mind Guren see's his sword thrown through Mahiru's chest who lays on the ground unconscious. Suddenly she screams in pain and Noya erupts out of her body.
She warns Guren not to say too much when he mentions he is a demon to Shinya and will always save him with his own power. Noya dismisses her words and says otherwise to spill all his secrets, which will make him feel much better. This annoys Mahiru-no-Yo and she tries to attack him with her sword only for him to grab it by his teeth, Noya points out that she can't suppress him any longer and he will eat her shortly instead. She simply silence him in annoyance. A weakened and exhausted Shinya see's Mahiru-no-yo but she simply smiles at him in silence, and before he can say anything Guren sprouts chains from his back and drains his squad power using Mahiru-no-yo and Noya to increase his own power.
After Guren arrives at where Shikama Doji battle with Saito. Shikama Doji sends scythes at Guren which are halted by both Mahiru-no-Yo and Noya. Mahiru tells Shinoa to hang in there as she will rescue her. Saito later uses his fangs to bite Guren to acquire the evil keys and his demonic powers. His actions surprise Mahiru for his betrayal but Saito is misled by Guren deception with Ferid help who arrives using Jigenso. With the help of Jigenso, Mahiru, Noya and Guren all acquire an evil key then they surround Shikama Doji with a sinister power entrapping Shinoa.
Forms and Abilities Edit
- Demon's Thrall: Mahiru-no-Yo may enter her host's mind and consume him with illusions in an attempt to break his will. If she wins, she gains control over his body.
- Basic Form: Mahiru-no-Yo appears as a black katana with a red streak down the middle. Merely drawing her increases her bearer's physical abilities significantly and calling upon her name increases them tremendously.
- Namanari: A human one step from becoming a demon. Mahiru-no-Yo has managed to turn Guren into one of these. In this form, Guren and Mahiru cooperate and have tremendous power. However, Guren's personality changes to a more demonic, heartless, and demanding one. It is unclear whether this is the demonic side of Guren that Mahiru began to create the summer before the Apocalypse when they were both human or if Mahiru is the one in control of Guren body.
Once Guren is possessed by Mahiru-no-yo, the blade would seem to have a mind of its own. The blade unsheathed itself from the scabbard and then proceeded to move around on air swiftly, beheading the noble vampire. In the manga, it was right after that did Mahiru appear as a ghostly apparition with mass-like demonic aura, hovering over Guren while his katana is equipped under her.
When Guren spoke of drinking the blood of human sacrifices, demons, and the progenitor , his katana drastically underwent a sudden change of color scheme. Through doing so, the katana itself went from being almost black in color to purely red of all blade length similar enough to vampire fire-class weapons used by the progenitors drank their blood. Not only that but something similar when Guren used a talisman to turn the color of a non-cursed gear's blade crimson from the light novel series, in the anime however he managed to turn his demon into completely from black to fully red without using or placing some talisman on it.
After merging with Noya, it should be noted that all Noya previous abilities are now in Mahiru-no-Yo, making her a very powerful demon.
- Mahiru-no-Yo can also be used to devour an enemy's attack. If Guren was on the defensive side, he would then call on the demon blade's name to assist him in battle when he was knock far back and being sent flying to the ceiling. He will then used the demon's power and ability to cushion his physical impact for safe landing.
- Mahiru-no-Yo can significantly increase Guren's physical abilities, and calling out her name would increase his power even more so. If Guren wishes to, he can invoke the demon's real name to have her possess him. This would cause Mahiru's apparition to appear and enshroud the blade and the arm wielding it with streaks of overwhelming flames, these flames are powerful enough to engulf an explosion in the midst of its vicinity, and even able to launch these flames at his opponent with one slash.
Additionally, Guren can utilize the power of the demon weapon for other miscellaneous purpose such as filling areas like the classroom with its immense demonic auras. Within the power's vicinity and range, victims pass out unconscious on the floor if they don't have the strength or willpower enough to overcome it. However, if the targets have high psychic resistance, used wards, or are a potential candidate for the Black Demon Series, they're not any bit fazed by Mahiru-no-yo's demonic aura. Merely drawing the katana from its sheath alone seeps blackish gases made from within in and out of the blade.
- Anime: Guren would go on and further use the power of his demon weapon, Mahiru-no-Yo to summon forth a red whirlwind cloaked with thin layer of crimson-like demonic aura. More so, the demonic aura can be seen concentrating all around its inner layer and then being destructively launch at targets through him upfront within his range. This red whirlwind was able to demolish the concrete wall of a building, pushing even half Shinoa squad.
- "Demand it! Ask for it! Seek out more power!!"— Mahiru-no-Yo to Guren, Chapter 17, "Cursed Guinea Pig"
- "Oh, Guren! You came. I was just thinking I'd like to see you."— Mahiru-no-Yo to Guren, Chapter 17, "Cursed Guinea Pig"
- "No, Guren. You won't. You'll follow me, right?"— Mahiru-no-Yo to Guren when Kureto tries to lure Guren to his side, Chapter 23, "Ambition in the Demon Army"
- "You always did have good friends, Guren. That's why it's imperative they don't find out. If the dead find out they've come back to life, they will turn back into the dust from whence they came."— To Guren, Chapter 54, "Sinner's Christmas"
- "If you tell him you saw me, Shinya will die. So shut up and stay silent, beast."— To Byakkomaru, Chapter 54, "Sinner's Christmas"
- "Aah... I can smell Shinoa's scent. She must be close. That... and I smell burning vampire... Aha ha! Someone is getting roasted like a side of beef."— To Krul and Ferid, Chapter 54, "Sinner's Christmas"
- "Aah, this brings back memories of high school. Once again, my lover and my fiance are fighting each other over my hand..."— To Guren, Chapter 56, "Loose-Lipped Vampire"
- "What a peaceful sleeping face. Guren? Why did you bring Shinya and the others here? You had multiple other options. In fact, there was no need to act like you had secrets to hide in the first place. If they discover what happened, they'll vanish. That isn't a risk worth taking. So why did you do this? ...You've hit your limit, haven't you? Your heart can't take much more of this. If you didn't let your friends know that you were keeping secrets, that you were weak... then you'd become a full demon. That's why you told them. The drugs aren't enough anymore, are they? You must do things that go against your ideals... or you'll become a true demon—"— To Guren, Chapter 56, "Loose-Lipped Vampire"
- "You look well. I'm glad. But why can't you see me? You would make a far, far greater subject for this experiment than I ever was, after all. Your demon hasn't awoken yet, has it? Your greed must not be intense enough yet. You need to fall in love. A need for love. A need for physical intimacy. Let those desires grow and run wild, until you don't care the east bit about the rest of the world. So which one do you want? One of the boys, perhaps? Which one do you want to warm you at night? ....Aah... I love you so much, Shinoa."— To Shinoa while Shinoa cannot hear or see her, Chapter 56, "Loose-Lipped Vampire"
- Her demon name Mahiru-no-Yo 「真昼ノ夜」 means "Midday's Night."
- In the manga, Mahiru-no-Yo is the only one who could sense that Shinoa demon isn't awakened yet, and she requires love and lust which eventually happened.
- According to the official Manga 8.5 Fanbook:
- Interests/Likes: Guren's future, ambition, lust, the "Seraph of the End" experiment
- Favorite food: Human hearts/minds, demons, cake
- Crush: Guren
- Though Mahiru-no-Yo is a demon, she retains all her memories in her previous life prior her death.