- 1 Family
- 2 Wives
- 3 Friends
- 4 Others
Nagisa is Kojou's younger sister. Due to Nagisa's health condition, Koujou has grown to be overprotective of her, leading many to believe he has a sister complex, despite his protests.
He is willing to go through great lengths for her; he once risked his life just to retrieve her straw hat that was at the edge of a cliff when they were younger. He also cares for her dearly. This is shown in Return of the Alchemist, wherein he sees the almost dead Asagi and loses control of his powers, but quickly stops when reminded of his sister.
She is Kojou and Nagisa's mother. He loves her and cares about her and keeps her away from harm as much as possible. Presumed to be divorced to their father, she gave Nagisa the chance to be a hybrid. He doesn't know that she knows about him being the Fourth Primogenitor or that she was keeping avrora body.
She is Kojou's grandmother. Kojou describes her as a "pretty strict old lady", similar to Gajou's depiction of her.
Kojou's father. Kojou's relationship with him is a little rocky as Gajou can be an irresponsible and careless parental figure, but they still love each other nonetheless.
Reina is the daughter of Kojou and Yukina Himeragi. It is assumed that they have a loving father-daughter relationship.
Moegi is the daughter of Kojou and Asagi Aiba. It is assumed that they have a loving father-daughter relationship.
A 14-year-old Sword Shaman from the Lion King Organization, Yukina was sent to observe the fourth primogenitor and was told to kill him if he becomes a threat. She despised him at first, but eventually grew to accept him. She is constantly following him everywhere he goes as his observer and as a result, has become very close to him. She was actually sent for this very purpose with the organization intending for her to be his first blood partner. She was the second to fall in love with him (after Asagi), following him wherever he goes. Her love for Kojou is so strong that she is willing to sacrifice everything for his good.
Yukina eventually becomes Kojou's Blood Servant, wife and have a daughter named Reina.
Asagi Aiba is Kojou’s classmate and best friend. Kojou and Asagi have known each other since middle school and Asagi has had strong feelings and a crush on Kojou ever since. Before Kojou became a vampire were Asagi and Kojou always seen together with Motoki Yaze. But since Kojou became a vampire have both Asagi and Kojou been spending less time together since Yukina Himeragi came into their lives and when Kojou’s life starts to change. Kojou then starts to spend his time more with Yukina instead. Kojou is also more absent from school and is less present in Asagi’s life. Both Asagi and Yukina have shown jealousy whenever Kojou is seen spending time with either of them. Early into the series, has Asagi both confronted and question Kojou’s relationship with Yukina.
Asagi eventually becomes Kojou's Blood Servant, and have a daughter named Moegi.
Avrora was one of the containers of original Fourth Primogenitor's beast vassals, who passed down the powers to her servant, Kojou. Although Kojou cannot recall any of his memories from the time he was with Avrora, he occasionally remember segments from his past. Avrora Florestina resided inside Kojou's sister, Nagisa, before being transfered into Hektos, another container of the original Fourth Primogenitor's beast vassals. Kojou cares for avrora greatly even stated by Yuiri that he loves her on the same level as Yukina and is willing to do anything to make sure she's happy even willing to give up his powers in order to save her from disappearing and if anyone was ever planning to do wrong to her he instantly enters a state of rage.
She later becomes Kojou's wife.
Yuuma is Kojou's childhood friend. They met when Kojou forced Yuuma to help retrieve Nagisa's hat at the edge of a cliff. Since then, the two along with Nagisa often played together before growing distant.
During the events of the Labyrinth of the Blue Witch, Yuuma and Kojou temporarily switched bodies. She cares about kojou fairy much saying that becoming friends with him was most important to happen to her because it was something she chose for herself. Before she left to asnwer for what she did she kisses kojou and states to yukina "I'll leave to you untel then Himeragi-san. Next time, I'm playing for keeps".
In season 4, Yumma returns to save asagi from being attack by Kasugaya Shizuri Castiella and the larvae on the highway. Yumma would be teleported with Kojou, Asagi, Yukina, and tank rider to the online island. On the online island they would battle against Magatoki Kato, Also known as the ouma witch, in which yumma would copy her magic book to defeat her with Kojou and co.
She becomes Kojou's wife.
She is a friend of Yukina Himeragi. Sayaka was ordered by the Lion King Organization to take charge of multinational magical crimes in the Foreign Affairs Division. She is the observer of Dimitrie Valte part time, just as Yukina was observing Kojou Akatsuki. Sayaka is very protective of Yukina, having known each other since childhood. They initially had a rough relationship; she was upset that Kojou made Yukina his blood partner, and blamed Kojou for involving Yukina in dangerous situations. She has androphobia (fear of men), which may have affected her early judgement of Kojou. Sayaka later takes a liking to Kojou, and allows him to suck her blood to unlock a new Beast Vassal, only to end up falling in love with him some time later. Similar to Yukina, she gets irritated when Kojou is seen with other girls, she still mistrusts men being Kojou the only exception.
She becomes Kojou 's wife
She is the eldest Princess of the Aldegyr Kingdom. Sayaka briefly mentioned about her in Episode 9 when she told Kojou that she was sent as an observer of La Folia. La Folia was seen by Kojou and he first thought her to be Kanase. When the topic of marriage came up when her and her family was visiting the island she immedialtely chose Kojou and ran to him when her father disagreed on her decision even willing to bet her virgininty in Kojou fight with Alader in order to achieve two goals one she knew he would win (an with this put an end the argue with his father and everyone else) and second to make him a member of the Whisper Garden. She is deeply in love with him and trust him blindly.
Later she becomes Kojou's wife.
She was a girl who was experimented upon by her adoptive father who had almost turned her into an artificial angel. La Folia revealed in Episode 11 that she was her aunt, as she was a child of her grandfather who had an affair with a Japanese woman, that at the later part of Amphisbaena arc was identified as Kanase Kensei's sister. She calls Kojou ”Brother”.She likes and cares for kojou greatly wanting to spend time with him whenever she gets a chance even when it gets embarrassing for either of them like when they went shopping for there school trip and asked him to come with her to the underwear store to know which kind he likes or when ever he walks in on her during or after a shower/bath. She loves him deeply and rarely leaves his side.
She becomes Kojou's wife.
She is the dark sword shaman that appears in the season 2 of the anime she often tease's him when ever there around each other.
She becomes Kojou's wife.
She is the vessel of Lilith, the world's strongest succubus. The bullying that Yume had gone through because of her mind-control magic made her think that her existence will always cause problems and harm to others, and she could not kill herself in a simple way because Lilith would simply find another suitable vessel and that person would also have to suffer. So she decided to assist Taishikyoku in their plan to control Leviathan, the strongest living weapon from the ages of the gods as she is the being with the strongest mind-control magic, only to betray them and reveal her true goal which was to die inside Leviathan, which has the ability to dissipate any entity into nothing and which will kill her along with Lilith. But Kojou saves her and gives her a meaning to her life.
She becomes Kojou's wife
She is a Sword Shaman from the Lion King Agency. She was nominated as a candidate for becoming Kojou's observer but was not selected. During his first meeting with Yuiri, Kojou noted that she was relatively normal compared to the other girls in the Lion King Agency; Yukina, Sayaka and Paper Noise have tried to kill him during their first meeting.
She has feelings for him, and is jealous whenever Kojou and Yukina are very close and often thinks what would have happened if she was chosen instead of her.
She becomes Kojou's wife.
Due to her friendship with Yuiri along with her rather obstinate nature, Shio is a bit stubborn about admitting her feelings for Kojou out of consideration for Yuiri, but she still values him very much and can depend on him when in trouble.
She becomes kojou's wife.
Introduced in Season IV Episode 1. First said to be Kojou's observer when they trained together at Onrai Island for half a year. Because Kasugaya has something of a tsundere-like personality, Kojou and her do occasionally get into arguments, but she cares for him nevertheless and was very shaken when he abruptly disappeared realizing her feelings towards him. Like the other girls, she loves him deeply and she hardly ever leaves his side.
She becomes kojou's wife.
He is Kojou's friend and classmate whom he met during middle-school alongside Asagi. He's 16 years old. Motoki is also a member of the Lion King organization and the real observer of Kojou, the fourth primogenitor. He is also Asagi's childhood friend and therefore often encourages her pursuit of Kojou. He's currently going out with Koyomi Shizuka and has told Kojou and Asagi that she's his girlfriend, despite having not held her hand according to Natsuki. He is an Esper who has the ability to manipulate special sound waves, but needs certain drugs or enhancers to strengthen his ability. Kojou is unaware that Motoki is his real observer but still supports him in his own way.
She is a teacher at Kojou's school and also the Witch of the Void. Kojou has a tendency to call her "Natsuki-chan" due to her body size and childish face. Although, this somewhat insulting nickname doesn't mean that Kojou respects her less than any older figures in his life, since Natsuki is the only adult that he had explicitly respected. He cares about her wellbeing even being emotionally distraut when he thought she died only to feel a since of relief later when he found out she's still alive. It's shown he finds her adult form attractive.
She was an artificial life form who had a Familiar installed in her The two seem to care for each other for some reason for astarte she was willing to betray her master abit in order to help him and secure his safety while for kojou when he confroted the deacon again he showed anger and disdain because he knew how dangerous it is for astarte by installing a familier into her shortening her life and after defeating astarte kojou brought her familier under his control so she can live longer. She later becomes a maid for Natsuki he does get worried and concered for her whenever she is injured or hurt.
She was the seal the of the 10th familiar. It is unknown how far her feelings is to Kojou but before she disappeared it seems she has grown to love him to extent that to leave him a goodbye kiss.
Hekto came to the island inorder to one destroy avrora body that kojou's mother was keeping second to save nagisa and avrora by using her own body to house her soul so she can finally be with kojou but before she can do this first she passed on the familiar she was keeping to yukina and then started to flirt with kojou infront of nagisa to incite avrora's jealousy to lure her out in the open to tranfer her soul into her body and properly to show her own feeling for kojou before she disappears using all her energy like december did.
She can turn into a dragon when she gets emotional. She is also a protector of Cain. She cares for kojou greatly even will to jump into the node after him in order to save him.
In their brief interaction in Alchemist arc, both of them can interact with each other, with Kojou taking the tsukkomi role to Nina's mischievous personality.
Kojou is wary of him, as Kojou sees him as someone that's ruthless and doesn't care about the well being of Itogami Island at all, doing things merely in the pursuit of pleasure with questionable methods. He can't understand Vatler's way of reasoning, much like the majority of the cast. Vatler's over-friendly gestures towards him sometimes make people misunderstand their true state of relationship, thinking that he's close to the older vampire. However, Kojou admitted to Vatler that despite the latter's tendencies to create problems in Kojou's life, he can't really "hate him to the bone."
Vatler: You wouldn’t rather finish me off, Kojou?Kojou: I don’t hate you that much.
Kojou seems quite relaxed with Kira, as the latter doesn't intimidate him and always treats Kojou and his friends nicely. His relaxed demeanor around him even made Asagi think that Kojou is into men.
Kojou doesn't have a civil relationship with Tobias the way he has with Kira. This could be attributed to Tobias' belligerent attitude towards him, that he showed freely by throwing insults to Kojou here and there when Kojou experienced some difficulties, that in Tobias opinion translated as "incompetence." However, their relationship seems to have improved when Tobias apologized to and even thanked Kojou at the end of Volume 15.