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Yuuki Anzai
Kanji 安斎 結貴
Romaji Anzai Yūki
Alias Alpha Two, Alex
Biological Information
Species Hybrid
Gender Male
Age 21
Height 176 cm / 5'9"
Hair Color Black
Eye Color Blue
Date of Birth January 15th, 1992
Unique Features
  • Longer piece of hair falling down his face
  • A mole above his lip
Biographical Information
Status Alive
Relationship Status Dating (Tsukasa Taira)
Other Relations Ibuki Takeya (Surrogate Mother)
Affiliation East Bay Public Security Section 1, Squad 3
Former Affiliation MPD Public Safety Division 5, F Squad
Occupation Police Officer
Hometown ONLO Orphanage; Obihori, Hokkaido
Manga Debut Line 1; Dark Side
Anime Debut Episode 1; Dark Side
Japanese VA Yoshitsugu Matsuoka
English VA Adam Gibbs

Image Gallery v   e

Yuuki Anzai (安斎 結貴, Anzai Yūki?) is the male protagonist of the Devils' Line series. He is a half-devil, half-human hybrid and a police officer who is initially a member of the F Squad in the MPD Public Safety Division 5, responsible to combat devil crimes as well as arresting devils. His occupation as a police officer utilizes his abilities as a hybrid.

He is a part of the 15th Hybrid Birth Project at ONLO in Hokkaido, where he was born and raised.

Although he isn't a pure-blooded devil, he still yearns for blood like any other devil but has a strict rule of not drinking blood. He has always despised the devil inside of him and devils in general, which is why he also was pessimistic regarding the co-existence of devils and humans. However, his thinking has been changing since he met Tsukasa Taira, who became his girlfriend throughout the series.

Following the F Squad's disbandment, Yuuki became a member of the East Bay Public Security Section 1, Squad 3, going under the alias "Alpha Two".


Yuuki Anzai was born and raised in Obihiro; Hokkaido, for the purpose of being made to be a part of the 15th term of the Hybrid Birth Project at ONLO. These devils are called "Children of Light" by some. He was born to the human researcher Midori Anzai and the devil serial killer Tamaki Anzai via artificial insemination. Unlike other pairs, Midori and Tamaki were genuinely in love and used the Hybrid Birth Project as an opportunity to have a child together. However, due to several reasons, Yuuki was carried by a surrogate named Ibuki Takeya. When he was born, ONL received full custody of him to carry out experiments of a hybrid. This is the reason why Yuuki's parents never got legal custody of him.

However, unlike Johannes Kleeman, Yuuki was excluded from the hybrid experiment due to lacking the healing ability hybrids have, being physically weak and bad with blood, and as so he wasn't experimented on at all. He was therefore placed in the orphanage in ONLO along with other devil orphans, but he still had to be monitored for ReMI (if his transformation would be insufficient or not). Being placed in an orphanage, the only information Yuuki got about himself is that he is a hybrid. He also grew up believing that he didn't have any parents or a family, but Yuuki claims that the ONLO teachers and the kids in his class became his family. Yuuki also became great friends with Tadaya Hiruta and Yuuko Yano, and the three would often play together.

One day, Yuuki who was playing hide-and-seek with Tadaya and the others, got stuck in a tree and unable to get down. He was then spotted by Kirio Kikuhara who helped him down. Soon after, they became acquainted and Kikuhara explained that he was a detective visiting ONL. Later, their conversation began getting more personal as Kikuhara embraced Yuuki and explained that he just wanted someone like him to become his comrade. He then proceeded to ask Yuuki to be his "friend" and follow him, and the boy agreed.

Anzai and Kikuhara

Yuuki and Kikuhara in the underground jail.

However, Kikuhara took him to the underground jail where there were full of transformed devils that had committed various crimes, all being held in the underground jail for research purposes. He told Yuuki that all the devils were the same as him, horrifying Yuuki as he thought he wasn't the same as them by being a hybrid. While Kikuhara led Yuuki to his father, he told him about his own past and how he killed his mother, this being the same path as Tamaki, Yuuki's father, took, by killing 15 people and becoming a mass-murdering serial killer. This revelation deeply shocked Yuuki as he simultaneously cried and threw up. The event scarred Yuuki and was the reason for his resentment of devils, but he had apparently blocked out this memory due to it being very traumatizing for the little boy.

When Yuuki was in ONLO High School, he had already thought about becoming a police officer with his best friend, Tadaya, as he wanted to be on the frontline protecting people from the danger of devils. So when he graduated from high school, he was assigned to the F Squad in the MPD Public Safety Division 5 in Tokyo.


Yuuki is a young man with a fit and muscular build who stands at an average height, 176 cm. He has light blue eyes and short, messy, black hair, and his most iconic feature is a longer piece of hair that falls down in front of his face. He gets a haircut in between the timeskip, but he maintains this feature. A small beauty mark sits on the left side of his upper lip. Yuuki inherited his mother's black messy hair, smile, and beauty-mark, but aside from that, he is noted to look exactly like his father. And since he is a devil who doesn't drink blood, he has prominent dark circles under his eyes.

He often wears a black shirt, light pants, and dress shoes. He is always seen wearing a silver ring with a black cross on his right middle finger. This ring is actually a device for monitoring his body temperature.


Yuuki's transformation into a devil usually follows a pattern. First, his eyes will start to turn red. Once they are completely red, his irises yellow and become cat-like. Veins will appear around his eyes. Then, simultaneously, his teeth will sharpen into fangs and his nails into claws. As a devil, Yuuki is stronger, faster, and has better reaction time. Depending on what prompts his transformation, it can happen slowly or nearly instantaneously. Feelings of passion usually mean a slow transformation, when confronted with blood it’s faster, and in life or death situations it’s even faster.


Manga Depiction

Anzai kid
Yuuki as a child.
Anzai teen
Yuuki as a teen, when he was in his last year of high school.
Anzai ch1
Yuuki's debut in the manga.
Anzai Devil
Yuuki in his transformed state.
Anzai Yuuki
Yuuki post-timeskip appearance.
Anzai East Bay
Yuuki in his new work attire.

Anime Depiction

Yuuki's full appearance in the anime.
Closeup of Yuuki.


At first, Yuuki seemed to be a withdrawn man shrouded in mystery. However, he has a strong sense of justice and can be confronting and sensitive regarding devil-related crimes and matters. He acknowledges the devils' influence in society, which is why he became a police officer - to protect people from the threat of devils. He is generally calm and collected but can turn very violent and dangerous, especially when it comes to protecting Tsukasa. He cares deeply for Tsukasa and his comrades, and will rush to their side whenever they are in trouble. This is seen when he transformed instantly after Tsukasa got shot. He let out a cry even while in his transformed state when he found out that she wasn't injured. He is warm and friendly towards those he cares about, and although he doesn't smile so often, he will smile and laugh and is happy around close friends like Tadaya, and also particularly Tsukasa, and will sometimes freely show his enjoyment towards various matters. But around his enemies and people he doesn't like, Yuuki will turn cold and blunt, and doesn't care whatever happens to them.

He is mature and responsible, but can at times act without considering the consequences of his actions in which he lets his emotions take the better of him. According to Johannes Kleeman (Hans Lee), Yuuki is easily emotionally manipulated and although he looks and acts tough, he is actually very gentle and soft. He also has it hard to despise people who despise him or have hurt him in any way, as he can easily sympathize with other people's past and upbringing. An example is Nanako Tenjo's hatred towards devils and her shooting him, Yuuki could never come to hate her as he sympathizes with the fact that she hates devils. As noted by Lee, instead of finding a resolution or talk about a problem, he blames himself for the problem and avoids it. He doesn't like holding grudges towards other people when it involves his own matters, and when he is at fault, Yuuki will push away his pride and apologize properly. But when it comes to Tsukasa, especially, he holds grudges and resentment towards people who have caused her harm in any way (if they are not genuinely sorry for what they did).

Yuuki is very self-deprecating, he despises the devil inside of him which causes him to have thoughts he doesn't want to have. He thinks he's filthy and creepy when in his transformed state, and not because someone said so, but because he himself thinks so. This is why he is rather shocked by the way Tsukasa is so accepting of him, and is reluctant to spend time with her in the beginning. He was also rather pessimistic towards devils and humans coexistence, but after meeting Tsukasa, his thinking regarding this matter has changed. They are always trying to make their relationship work, in their own way, but Yuuki is still self-conscious. But although he still isn't fully accepting of himself, Tsukasa has helped Yuuki is a lot of positive ways and gave him a boost in his self-confidence. And exactly because of how dear Tsukasa is to him, he decided to break up with her for a while to sort out of his feelings and clear his confusion, and then see her again. He just doesn't want to put Tsukasa in dangerous situations and make her worry. Although they had separated, they are now together again and states that they will always stick by each other's side no matter what.

In Tsukasa's presence and when she says something sweet to him or displays jealous behavior, Yuuki turns very flustered and embarrassed. She is the only person Yuuki shows this side to. It is mentioned that the majority of the times Yuuki has transformed is when he's lusting for Tsukasa or when it revolves around her. Sometimes, his lusting for Tsukasa resulted in some private perverted acts, such as in one time after their first bloodlust training session when the thought of Tsukasa being sexually excited by him strongly urged him to masturbate.

He also has some comical sides to him as well, and can at times be scolding, short-tempered and have arguments with Lee who is the complete opposite of him.


Yuuki Anzai's Statistics:
Combat strength Skills Eyesight
60/100 Transformation Left 3.5 / Right 3.4

Fighting Skills and Strength[]

Yuuki is a capable police officer and is relatively strong. One of his strong points is how fast he is, as he can vanish and reappear in a short amount of time. He can also jump very high, up to heights as tall as telephones poles.

Anzai Mounts A Telephone Pole

Anzai balancing atop a telephone pole.

While Yuuki is strong, he doesn't want to use his maximum power for fear of hurting his opponents and making them bleed. So when he is in his untransformed state, Yuuki can easily be defeated by other devils or a capable human, such as Megumi Ishimaru. In his transformed state though, Yuuki becomes much more physically stronger, as he can use make maximum use of his muscle power, almost to 100%. He also becomes much faster, and since his senses are sharper and his reaction time better, he can more easily defeat his opponents and dodge attacks. He can defeat several people after one another. However, he tends to let his guard down sometimes.

Transformation and Healing[]

Up until he met Tsukasa, Yuuki's bloodlust had always been slightly lower than average and he could control it quite nicely and managed to refrain from drinking blood for 21 years. His transformation was also quite insufficient (ReMI) since he never lost control of himself when he transformed. However, his bloodlust awoke after meeting Tsukasa, who became his girlfriend. One of the feelings he awoke was lust and sexual drive, which is closely associated with bloodlust. His mother, Midori, mentions that Yuuki's case of transformation is called "indefinite ReMI", which indicates ReMI where the physical nature changes due to a certain trigger. This is normal for hybrids as Yuuki.

Ever since his bloodlust awoke, his transformations have become much more dangerous as he can lose control of himself and it also takes a toll on his body. His transformation becomes more extreme the more serious the situation he is, which can make him lose his mind and not be able to control what he's doing, as well as his fingernails and fangs growing to incredible lengths.

Anzai half transformation

Yuuki in his stabilized, half-transformed state.

This has only happened to Yuuki is the entire series. His healing ability also blossomed after waking the bloodlust, so he can avoid death if given enough blood to heal wounds.

However, he does struggle with bloodlust a lot and feels urges he sometimes can't control, which makes him easily lose control. His trigger for transformation is anger, especially when it revolves around Tsukasa or when she is hurt by someone. Recently, Yuuki has become better at managing his bloodlust and can halfway stop his transformation is his eyes, making only the top halves transform. Yuuki has realized the conditions he needs to stabilize his transformation are controlling his own anger and having Tsukasa's forgiveness. His stability has been achieved only a few times and was activated by anger and forgiveness, but if lust wins out, he will revert to the original transformation pretty quickly.


Tsukasa Taira[]

After the incident with Akimura, Yuuki kissed Tsukasa upon seeing her blood. Although he planned to never see her again, he was worried about how she was feeling after the incident with Akimura. He then regularly started to visit her and quickly fell in love with her. Yuuki was initially hesitant to spend time with Tsukasa due to his thinking that humans and devils shouldn't live together. He was also very shocked at how accepting she was with him, which is why he began seeing her as a person he had to protect. Yuuki began to take more advice from people around him to control his bloodlust and become a better police because he wanted to be able to protect Tsukasa. He cares for her well-being more than anything and will turn very violent when she is attacked or hurt in any way, he doesn't want to expose her to any kind of danger. Yuuki also tends to become jealous when other guys swoon over her, but doesn't push on it. After they become an official couple, they are seen to be a very a straightforward, loving, trusting and dedicated couple. At the same time, Yuuki is very scared of hurting Tsukasa or coming off as indecent, in which he troubles himself to stay away for the fear of hurting her. He loves her so much that he doesn't care what happens to himself as long as she is safe. He sees her as his family, and the place he wants to go home to every day. He likes how kind and straightforward she is, as well as how she always faces him head-on. Yuuki thinks this is what made him fall for her. However, he has many negative and mixed feelings, such as the bloodlust he feels for Tsukasa, which he absolutely doesn't want to act on. Rather than that, the fact that he had exposed Tsukasa to such much danger and his draining thoughts about the co-existence of devils and human, made him break up with her for the time being so he could sort out his feelings and give Tsukasa a clear answer. After getting back together, they are stronger more than ever and does everything to be able to live together.

Johannes Kleeman[]

Yuuki was initially not particularly fond of Lee and did not trust him at all. He was suspicious about the fact that Lee spouted many facts while he didn't reveal any information about himself. Yuuki was also absolutely enraged and hostile that Lee gave him blood during their first meeting, and most of all that Tsukasa offered Yuuki to drink her blood, which was caused by Lee telling her things like devils drinking blood could increase their lifespan. However, Lee gives him blunt comments like with the way he is now, he can't protect people close to him. Yuuki couldn't trust him, but he knows he's right and takes his words into consideration and tries to improve himself. Lee also helps Yuuki with his bloodlust training and trying to control his bloodlust. Yuuki starts to open up to Lee, and they start to become "friends" as he makes a slight effort for Lee to stay with the F Squad and actually come back to them rather than going away somewhere else. Although Yuuki claims he doesn't worry about Lee whenever he disappears since he is so strong, he cares about him enough to check up on his wellbeing and him actually coming back. However, since they are complete opposites and share very different viewpoints, Yuuki often grows annoyed at Lee and butts head with him.


  • The name Yuuki means "tie, bind" (結) (yuu) and "valuable" (貴) (ki).
  • Yuuki's surname Anzai means "peace, quiet" (安) (an) and "religious purification/purification, Buddhist food, room, worship, avoid, alike" (斎) (sai/zai).


  • When Yuuki becomes drunk, he tends to be sleepy and clingy with people.
  • Yuuki's average sleeping time is 6 hours.
  • As a child, Yuuki was great at molding, especially penguins. He even considered becoming an artist in the future when he was younger.
  • Yuuki's favorite foods are milk and chocolate.
  • Yuuki prefers having slip-on shoes.
  • Yuuki has had a class 1 driver's license since 2010, which means he got it when he was about 18 years old.


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Characters of the Devils Line Series
Main Cast
Yuuki AnzaiTsukasa TairaJohannes KleemanAkio KanoJuliana LloydTakashi SawazakiToshiro SakakiRyusei Yanagi

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Keio University
Teachers Keiji Ochiai
Students Miwako TodaShouta AkimuraTsukasa Taira
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MPD Public Safety
F Squad Juliana LloydMegumi IshimaruRyusei YanagiTakashi SawazakiYousuke AsamiYuuki Anzai
A Squad Kirio KikuharaYoshiyuki Uno
B Squad Takeshi Makimura
C Squad Masakazu TakimotoNaoya UshioYuu Kagasaki
Others Aya ShinjoKaname Yukimori Kenichi Morisawa Shizuka MachidaTadaya Hiruta

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Active Members Kaname ShiraseKirio KikuharaAkihito KanzakiYuriko Hyuga
Former members Kenichi YoshiiKouhei Nakamura Mayu SumimoriMegumi IshimaruNanako TenjoNaoya UshioRen Murakami Takeshi Makimura

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Research Haruto MinegishiJulius KurtzMasami KomatsuIbuki Takeya Maiko Hashimoto Midori AnzaiMikaze Akimura Shouta AkimuraTamaki Anzai
ONLO Johannes KleemanTadaya HirutaYuuki AnzaiYuuko TamaruKubo
R2PC Kaname ShiraseSusumu Sofue

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Other Characters
Civillians Akio KanoEkaKaori SumimoriKatsuki SumimoriKousuke ChizuMakoto TamaruMana SumimoriMio SumimoriMiho Kaneda Misaki TakenamiSaki SumimoriSayuri Tenjo Shizuku Takenami Toshiro SakakiYasuhiko TakeyaYuzuru Kikuhara
Bar Cross Minami Okino
Bar CALM Kiwako Oe Ryunosuke KatagiriWataru Akase
Meteorology Plus Yuichi UtsumiYuriko Hyuga
Asahi Railways S.S TamiyaYousuke NakamuraYoriko Narumi
Shirase Hospital Akihito KanzakiFeng Jing