Yūichirō Hyakuya

"I... I don't care what people call me. Call me a demon. Call me a monster. Whatever. It's just... If I can keep my family safe... If I can protect the people who took in someone like me, I'll be happy... Everyone here is my family."

- Yūichirō to his squad

Yūichirō Hyakuya (百夜 優一郎), birth name Yūichirō Amane (天音 優一郎), is the main protagonist of the Seraph of the End: Vampire Reign series. He is a member of the Japanese Imperial Demon Army as well as Shinoa Hīragi's squad in the Moon Demon Company. He, along with Mikaela Hyakuya and a few others, possesses the "seraph" gene, which is relevant to the forbidden taboo and the focal point of the story, "Seraph of the End."

He also appears in prequel materials Seraph of the End: Guren Ichinose: Catastrophe at Sixteen and Seraph of the End: The Story of the Vampire Michaela.

NOTE: "Yu" (one "u") is spelled as "Yuu" (two "u"s) when he first appears in the Catastrophe LNs, but this becomes "Yu" later on and matches the manga. His first name is always spelled "Yuichiro" with only one "u." Therefore, we will spell his nickname as "Yu" here.

Human
Yūichirō has medium length black hair which can be considered quite neat and messy at the same time. He possesses sharp green eyes which fall under his thick eyebrows. His eyes are large compared to most other male characters in the series.

As livestock, he wears the standard white uniform with short sleeves and a hood.

In chapter 2 of Vampire Reign when he is sent to school for his behavior, he is shown wearing his school uniform, gakuran with a standing collar that is black with teal trim. The collar and the top buttons of the jacket are unbuttoned, revealing is a white shirt underneath. He wielded a standard demon katana until he is promoted into the Moon Demon Company.

As a private of the Demon Army, he wears the standard JIDA uniform which consists of a long-sleeved black coat with light green details including the shoulder epaulettes which has a brown Sam Browne belt passing diagonally over his right shoulder and two rows of gold buttons on the front. Along with that, he wears a pair of white gloves and a white web belt with a gold waist-plate. He also wears the uniform trousers and black boots which go over the trouser's leggings. Yu keeps his katana on the left side of his hip. Sometimes he can be seen wearing the JIDA hat, and often wears the JIDA cape as well.

Demon
Yu's eyes become scarlet, sprouts two black horns from his head, and his teeth become pointed while curse marks appear on the side of his face.

Seraph of the End
In his incomplete seraph form, Yu's left eye turns dark and bleeds while a massive wing-like structure sprouts from his upper left shoulder. As a full seraph, Yu has a single pair of irregular black wings as a result of Asuramaru trying to prevent the transformations, both of his sclerae are dark with gold irises, and the edges of his hair become white.
 * Anime: In his incomplete seraph form, the transformation is more extensive. Yu's left eye eventually turns into a black pit, and his right eye becomes red. Then in his full seraph form, Yu's wings are brown cord-like limbs and the edges of his hair do not become white.

Human
Up until his teen years, Yu started off as moody and antisocial due to the tragedies in his life. As a young child, he saw himself as a demon that no one would love, yet he still held out hope of finding something good in this world. At first, Yu wanted nothing to do with Mika and the other Hyakuya orphans and even challenged Mika to a fight.

Shortly after though, when Mika puts Yu in charge of watching over the kids alongside him and Akane, Yu took on the role of the aloof, yet kindhearted older brother. After losing them, Yu reverted back to being a moody antisocial rebel with a thirst for revenge against the vampires that killed his family for another four years.

Eventually, when Yu opens himself up, he becomes a hot-blooded youth with a kind heart. which shows when in his fearlessness and somewhat reckless actions show when he attacked a Horseman while ignoring orders, and is noted that this wasn't the first time. Yu is often called an idiot by those who know him. He is a very narrow-minded person, whose only goal is to annihilate all vampires because of what they did to his "family," and he will overcome any type of challenge in order to accomplish it. He swore to exterminate all vampires for killing his family, especially Mika.

Despite this, he has a soft spot and worries about his friends first and his goals second. Ferid Bathory considers this attitude to be "cute". Because of this, he empathizes with others who put their family first, as seen when a civilian girl gave his squad false information because vampires are holding her family hostage. After learning why she deceived them, he tells the girl that she did the right thing to save her family. He feels guilty for abandoning Mika and has nightmares about Mika's death for four years until he makes friends with Shinoa and Yoichi. After learning Mika is alive, Yu's personality changes in response and he grows more mature, as noted by Shinoa. He puts more effort into being patient and calm and making friends, and immediately amends his worldview to include Mika even though he is a vampire. His dream of wiping out vampires takes second place to reclaim Mika. Regardless, even though his best friend is now a vampire, Yu still slaughters them without mercy or hesitation. After Shinjuku, he becomes closer to his squad members and makes Guren promise to help him take Mika back under the promise that Mika will be useful to him, as he comes from the same orphanage as Yu. Additionally, friendship and bonds become more important to him, as shown in a mental battle against Asuramaru, to gain more power or else lose his body, he calls Asuramaru his friend and convinces Asuramaru to yield to him.

Rather than revenge, his primary goal changes to protecting his new "family," in order to avoid a repeat of past events. In Nagoya, he surprises Narumi's squad by memorizing all of their names and promising to protect them.

Similarly to how vampires do not bother to remember human faces and only think of them as "humans" or "livestock," Yu only sees vampires as "vampires" or "bloodsuckers" without bothering to remember their names or faces. He does not even recall the name of his vampire target in Nagoya. The only exception to this rule is Mikaela Hyakuya, who he still greatly cares for, and as Ferid Bathory was the one who murdered his fellow orphanages, Yu still cleanly remembers his resentment at Ferid and has been seen to rage when they meet again.

Aside from this, Yu shows to have a somewhat weird sense of humor, as shown when he teased Shinoa for her height.

1,000 years ago he was in good terms with Ashera Tepes and been with Sika Madu for a long time even obeying his orders, despite being used by Sika Madu all along.

Seraph of the End
During his first transformation, he goes berserk and attempts to kill any human nearby. He displays no interest in vampires and recognizes no one. He also mutters that sinners must die, and he must kill all sinners.

Upon his second transformation, he curses the tainted humans and plans to turn them into "pillars of salt."

Namanari
In Yu's demon form, he acts like a standard demon. He wants to kill and destroy anyone nearby and screams and rages about being restrained. He even attempts to trick Mika with his blood and promises to run away with him if only Mika will set him free.

Thanks to Shinoa and Mitsuba's restraints, he has been unable to act on his desires.

When he returns to human form, he does not recall any of his actions as a demon. Despite this, he appears utterly nonplussed about losing his humanity, much to Mika's distress.

Until he receives medication for keeping the demon side restrained, he acts colder about everything, and Asuramaru notes he is able to think much more rationally without all of those emotions in the way. After receiving the medication, his personality returns to how it was before he became a namanari.

Dark Ages
In the dark ages, Yūichirō accompanied Sika Madu in buying Ashera from imprisonment and obeys his master's order in freeing Ashera. When Ashera asks if he is a bought child too, Yu just stares at him silently. He does not know and asks Ashera if he himself was brought, Yu does not remember anything. Yu asks who he calls Sigama whether he was brought but concludes that Sika Madu does not know either, but contemplates that it is possible he was before following Sika Madu.

When Sika Madu asks Ashera if he is hungry, Yu interupts that he is really hungry. He answers Sika Madu that whilst he ate not too long ago, enough to feel like he would pop he is hungry again, and asks why is that. Replying to Sika Madu, Yu asks what a growth spurt is and whether it means he will get to be big like him before abruptly stating that he is really hungry once more. He then cannot talk over his eating. A bowl breaks as Yu collapses to the ground as he shares that his tummy hurts, he is going to pop. He ate too much but asks if Sika Madu thinks if he has gotten bigger, or smaller when he is told overeating may be bad for ones health, Yu cannot eat another bite. Walking through the streets Yu asks Ashera how he knows his name when he speaks to him. Pointing to himself and waiting expectantly, Yu imitates Ashera awaiting for him to asks how Yu knows his name so that he could copy Ashera in saying that Yu heard Siga Madu call him that. Yu then asks whether he is amazing for being able to tell Ashera's name, in the same manner as Ashera learnt his name, from Sika Madu.

As they continue walking, Yu asks what Ashera means when asked about his duties. With the question simplified to what he does between waking up an sleeping, Yu answers that he eats, reads when Sika Madu tells him to then plays, eats again then sleeps when he is tired. Yu guesses it is the case that he plays all day when Ashera points it out to him. As to whether Yu is a slave he wants to know what one is, he also does not know if master buys child slaves a lot. One question Yu can answer after clarification is that Sika Madu does summon him to his chambers, just sometimes though. Back at Sika Madu's manor Yu takes a toy snake from a box and asks whether Ashera is going to play. In the face of Ashera's reluctance Yu insists that it is a lot of fun, adding sound effects to the snake. He is delighted when Ashera says he will play that with him remaining oblivious to Ashera's concerns on his survival chances.

By night time Yu stands by himself in Sika Madu's room. He is staring out the window when Ashera finds him at which point Yu holds his own face and yells as six seraph wings emerge from his back. In this state he expresses a seething hatred for humans for dabbling in the taboo and wishes to kill them. His eyes have changed and he glares at Ashera before being told to calm himself by Sika Madu. Hearing that an adjustment had been made on him so that he could stop does not prevent Yu from leaping into the air towards Ashera before being grabbed at the neck by Sika Madu. Feathers fall off him as he demands to be let go, he must kill all humans. Yu's rage intensifies and results in him using his right hand to cut his left arm clean off. He is able to break through the door where repeating his murderous intent he stabs into Ashera's chest. With this done he shouts and flies out of Sika Madu's manor towards the moon still holding Ashera. Hovering in the sky, Yu says the world is full to brimming with filthy, unrepentant humans and he must kill them. His murderous denouncements come to an end as Yu is unexpectedly decapitated by Sika Madu behind him and he falls to the ground below. With Yu's blood having accidentally got into Ashera, Yu's head is picked up by Sika Madu and his blood is allowed to drip into Ashera's mouth.

He is found sat on a throne in a large room container multiple containers each with a single black substance within. Yu's head is reattached but he remains unresponsive to Ashera, Sika Madu and the black matter above him that sinks extensions of itself into his head.

21st Century
Yūichirō Amane was born on October 16, 2004. During his childhood, both of his parents screamed that he was a demon spawn. Yu's father tried to kill him, claiming that he had to kill the seraph of the end now or else the world would be ruined. His mother also goes mad and tries to burn their apartment down with Yu inside, but he is saved by Saitō of the Brotherhood of a Thousand Nights. His mother screams about killing the demon before she sets herself on fire, burning herself to death and committing suicide.

The Hyakuya Sect then used Yu in experiments and later erased his memory of them. On the day of the Apocalypse, Saito brings Yu to one of the orphanages and leaves him in Mika's care.

Book 3
In chapter 3, the 6 p.m. news shows a fire at an apartment complex. A disheveled woman in her mid-twenties with long, silky black hair then steps out of the crowd and screams for Yūichirō. She screams about a demon and says the fire should never be put out, and says the demon child should be killed immediately. She then lights herself on fire which causes firefighters to tackle her.

Saitō from the Thousand Nights appears and approaches the camera before the footage is cut.

Book 5
Mahiru visits Yu, who is being experimented on and abused by the Hyakuya Sect. She asks him about his reason to live and if he has no right to live if he is a demon. Yu does not know how to answer. Since his mind has not broken from his experiences, she tells him he will find an answer one day. A researcher says he will erase all memory of this conversation from Yu’s mind.

Book 7
Yu is being driven by Sait ō. He tries to get the man to answer where they are going, and Saitō eventually tells Yu that he is evacuating him to the Hyakuya Orphanage far from Shibuya. When Saitō brings up with the prospect of Yu getting along with the kids like him, Yu shoots it down as he believes his parents' claim of him being a demon child, hence no one would care about him. Saitō doesn't believe it, but Yu brings up his (not) mother's death, and it brings tears to his eyes. Saitō tries to encourage Yu to smile, but Yu refuses and turns away to look out the window. He ignores Saitō's comments, and even the option for him to die by jumping out of the speeding car, which the boy remained sitting with only his shoulder quivering a little.

Yu then tells Sait ō that he will not die because there is something good in this world which the man doesn't believe, so the boy explains about the scientists talking about him meeting someone and being blessed by something. Though when Sait ō brings up Yu making friends at the Hyakuya Orphange, the boy continues to believe there won't be any friends over there.

Book 1
In Sanguinem in 2016, Mika donates his blood, cringing as the needle pierces his neck. He chats with Yu, who is sitting next to him. Mika thinks Yu is kind because he always maintains the children's hope about defeating vampires.

Once they finish up and leave, Yu asks him what is wrong and says Mika is spacing out. Mika only says he feels tired after donating blood. Yu prattles on about killing vampires again before telling Mika to not carry everything on his own shoulders. Mika knows that one wrong move will get him killed, and he cannot risk Yu dying. If they both died, then who would take care of the younger children?

Mika tells him not to worry and asks what Yu's surname is, but Yu cannot remember. Yu asks Mika about his family since he does not look Japanese. Mika's mother was Japanese but his father was Russian. Mika says his last name was Shindō. Mika says all of the orphans use the surname Hyakuya because they are all family.

Mika sees Ferid Bathory's mansion and splits off from Yu.

Shibuya Arc
Yu calls to Shinoa who is currently undergoing the transformation into a vampire. He is pushed away by Kureto and told to get lost and watches as Shinoa is removed to an examination room. Yu asks if Kureto can save her blaming himself as Shinoa let that monster possess her to save him. He confirms with Kureto that he met that thing, that it knew him and Asuramaru from some time ago. Focusing only on helping Shinoa, Yu speaks candidly despite Mika prodding him to not hand out information that he is sharing for free. Though Yu does not remember anything, in order to save Shinoa he offers himself for examination to uncover potentially helpful memories. His offer is accepted, at once being taken away by Kureto's guards where Yu is verbally robbed of his freedom and declared an experimental subject. Yu accepts anything they want to do to him, so long as Kureto swears he will save Shinoa before being led away.

Yu from history is remembered by Urd Geales beside the first when he was alongside Rigr Stafford.

Back in the present, Yu struggles against the two guards taking him away. He demands they forget about him, and to promise to find a way to keep Shinoa from turning into a vampire. His sword has been taken as Yu tells them the monster knew them both from ages ago. and continues to protest as he is trailed by Mika.

He awaits on a stretcher with Yoichi, Mitsuba, Narumi with Kimizuki nearby as they hear what sounds like a battle. Yu asks what nearby scientists are waiting for, shouting that he is supposed to have info on that monster buried in his memories. He tells them to hurry up, as if that thing takes over Shinoa it will be too late. Aware of the electrical needle being moved towards his neck, Yu reassures Mitsuba who has remained behind with him that he will be fine and that she should go be there for Shinoa. Yu firmly tells the scientists to go ahead, he needs to remember what he knows of that monster so he can go save Shinoa before having the needle stabbed into the back of his neck and his eyes change dramatically. Unconscious, he is unable to help Mitsuba who has been attacked by the very scientist helping unlock Yu's memories. Revealed to in fact be a member of the Hyakuya Sect, Yu is taken to a new area via a tear in reality. In his mind with Asuramaru, Yu lays on the ground with two spears in his back as he faintly tries to remember.

Unconscious, Yu is brought by the agent before Saito who orders him to be taken to their lab in Ikebukuro. With the Hyakuya Sect's attack on Shibuya in full swing, in the north ward of the city Yu is chained and being transported on a stretcher. He wakes up to witness the fight between Saito and Shikama Doji who is inside Shinoa's body. Noting the explosions he asks why is he tied up, he cannot get them off. Addressing those pushing him along he asks where are they taking him.

Natural Abilities
Yūichirō seems to be an excellent swordsman, as he was trained by Guren himself. He is capable of taking down Horsemen with both an enchanted gear and Cursed Gear blades, and has proven to effectively fight and slay common vampires.

He is also a "Seraph of the End" hybrid with 1/10th of him being not human due to him and his old family being experimented on by the Hyakuya Sect. After he overdoses on the curse supplement to save Guren from Crowley, his non-human part increases.

Enchanted Gear
Mass-produced cursed gear, these demon weapons are much weaker, usually of the yaksha or myo-o series, as they increase a regular human's strength by three to four times. Yu wielded one in the form of a katana, and was able to use this gear to easily slay a horsemen and hold his own against the escaped vampire, Noin Teta.

Cursed Gear
These weapons are capable of increasing a person's strength by seven times.
 * Asuramaru (阿修羅丸): Asuramaru is a possession-type demon weapon of the Black Demon Series, where he takes the form of black katana with a green edge. Whilst in use, the blade develops a thick green aura. Like Mahiru Hīragi, he can call upon Asuramaru to fully use its power to attack opponents.
 * Asura-Kannon: A special technique using Asuramaru that materializes dozens of floating swords.

Experimentation

 * Drugging Up: Like other soldiers in the JIDA, Yu takes a supplement to increase his synchronicity with his demon to 150% for 15 minutes. After that time is up, this synchronicity drops to zero. There are numerous unpleasant side-effects, and officers only resort to this as necessary.

By using the golden trumpet within his consciousness, Yu undergoes a drastic transformation. As a completely awakened Seraph, he is the Second Trumpet referred to as the "King of Salt" (塩の王). His main power consists of turning every living being into pillars of salt. Additionally, he can also create a spear made of salt that can block Abaddon's destruction ray. He later has full control of his Seraph state.
 * Seraph of the End: By swallowing a special tablet produced by Guren, Yu can lose his mind and undergo a painful transformation. Although extremely powerful, he goes berserk and attempts to kill any human nearby. Guren causes this transformation to end by making Shinoa hug Yu. The transformation ceases, and puts Yu into a coma for a week. It takes five days for the drug to get out of Yu's system, and even after that, he feels tired. Yu has no recollection of the events that occur while he is transformed.


 * Anime: He attacks both vampires and humans without discrimination while he only wants to kill humans in the anime and orders vampires like Mika to get out of his way. Additionally, his power is demonstrated more in the anime when he swings his sword and creates a plume of black energy the size of a tall building with a ring of light around its base.

Trivia

 * Yūichirō 「優一郎」 translates as "kind first son."
 * His parents spelled it with the kanji for "gentle" in the hopes that he would grow up to always be kind and gentle to whomever he met. Mahiru believes this idea is ludicrous for anyone less than a god.
 * Due to Yu's name, it is considered a pun when other characters say Yu is kind (優しい). Kindness is also considered one of Yu's actual primary character traits.
 * Hyakuya 「百夜」 means "hundred nights."
 * Amane 「天音」 means "heavenly sound."
 * He was one of the first characters designed, along with Mikaela and Guren.
 * Yūichirō is the only member of Shinoa's Squad who does not have a known biological sister.
 * In the Michaela light novels, Mika asks Yu what his surname was, but Yu can no longer remember that his name was Yūichirō Amane and solely goes by Yūichirō Hyakuya.
 * When Yu first forms a contract with Asuramaru, it is revealed that 1/10th of him is not human. He becomes even less human in chapter 34 after overdosing on curse stimulant pills. At the end of chapter 40, he chooses to erase his humanity completely.
 * Since he lived in a vampire city for 4 years, Yu is nearly illiterate and only writes phonetically without using any Kanji. Vampires have no need to educate livestock on how to read or write.
 * Mika is the first vampire shown to bite Yu. Yu offers his blood three times before he finally convinces Mika to bite him in chapter 36.
 * At the age of twelve, he was 145 cm tall and weighed 38.2 kg.
 * According to the Q&A with Kagami, Yu's seraph form has black wings because his demon tries to stop the transformation.
 * In the popularity poll, Yu earned 3rd place at 3,536 points.
 * According to the Manga 8.5 Fanbook:
 * Interests: Worrying about Mika / Driving cars.
 * Favorite Food: Curry, Shortcake (because the children at the orphanage said they wanted to try birthday cakes).
 * What he looks for in the opposite sex: “Shut up.”
 * According to the TV Anime 108 Fanbook:
 * It's been stated that Yu 's favorite color is blue because it reminds him of the blue sky he saw once he escaped from Sanguinem.
 * Yu's favorite pajamas are yellow.
 * One of Yu's dreams is to drive a fast car.
 * Yu's goal after saving Mika is to eat curry.
 * Yu does about ten push-ups and additional training daily.


 * In his previous life with Ashera it is shown that he already has Seraph powers as the latter grew angel wings behind his back.


 * In one of the OVA's, Krul whispers in Mikaela's ear that Yu is a **********, and by the creators of the show later translated this to "Yu is a homosexual", although no other evidence has been provided to prove this point besides in the OVA.

Book 5

 * "Who are you? Are you here to kill me, too?"— To Mahiru upon meeting her the first time, Prologue


 * "But I don’t! My mom and my dad said so! They said that I was a demon and needed to die! That as long as I live, bad things will keep happening… so instead I need to die! My dad was always so nice to me, but then he pulled that knife out… And then my mom said I shouldn’t be alive anymore. She said I’d be happier dead. Because I’m a demon, a monster, and I’ll ruin the world… It’s… It’s my fault that they’re dead… Mommy! Daddy!! Ahhh!"— To Mahiru, Prologue


 * "B-But… How is someone like me living worth anything?"— To Mahiru, Prologue