The next day, after meeting Hikari's human twin sister, Himari, Tetsuo spends some time with Hikari to learn some facts about real-world vampires. Reading up on various folklore, Tetsuo comes up with an idea and has Yuki take a hot foot bath while reading some of the more grim legends surrounding snow women. That said she get more interested in Tetsuo. Impressed by Hikari's determination, born from a promise made with Himari, the girls apologise to Yuki after she explains why she acts cautiously around others. Her impression of him changes, however, after Tetsuo explains the importance of understanding demis by recognising both their human personalities and their troubles with being demi-humans. She often tries to make her sister act more mature, but is unable to.
. However, in recent years, they have become accepted as members of society. Due to the aphrodisiac effect her body produces, she constantly has to take precautions to avoid inadvertently seducing men and other male students, such as wearing a tracksuit to hide her body and taking the first and last train of the day to avoid crowds. Despite their constant bickering, they care about each other and have many similarities such as similar tastes in food and fashion. Volume 2 ranked at number 13 on the manga charts during its first week, selling 39,876 copies. Later, Yuki becomes panicked after she overhears some girls badmouthing her behind her back, claiming that she is being full of herself, and seeks out Tetsuo's help.
Hikari's mother is a vampire and her father is a human. Later, Yuki asks Tetsuo to help her learn how to control her snow woman abilities in order to beat the summer heat. Afterwards, Yuki goes to spend time with Hikari and Kyōko and becomes closer friends with them. A thirteenth episode aired on 29 June 2017. The series' scripts is written by Takao Yoshioka, character designs are done by Tetsuya Kawakami, and music is composed by Masaru Yokoyama. Using what he had learned, Tetsuo arranges with the principal to allow Kyōko to use a backpack instead of a regulation bag so she can carry her head around more easily, a deed that is only noticed by Sakie. As the next term begins, Tetsuo converses with an invisible woman named Matsuri.
While Tetsuo questions Hikari on the connection between bloodsucking and romance, Kyōko tells Sakie about her crush on Tetsuo and asks for some romance advice, despite Sakie's lack of actual experience. While Sato's nature as a succubus leads males to become attracted to her, she herself develops a crush on Tetsuo after coming to believe he is immune to her aphrodisiac effect. Later, Hikari holds a contest among the others to decide whose arm she'd prefer to bite. She initially found it hard to make friends as people found it awkward to talk to her without bringing up her detached head in some way, despite her own acceptance of the concept and desire to joke about it. Hearing Souma's theories on a dullahan's space-time potential, Kyōko starts to take an interest in researching more about dullahans. As the girls enjoy themselves, Sakie attempts to ask Tetsuo out while Kyōko has a discussion about the legends concerning dullahans, leading to her first experience putting her head underwater. The next day, the vice-principal reverses his decision, acknowledging how Tetsuo's efforts have inspired both his demi-human and human students.
The series began serialization in 's Young Magazine the 3rd magazine in September 2014 and is being published in English by. Himari is always looking after Hikari to make sure she doesn't get into trouble or stay out too late. Since she can't move her head by herself, she is always longing for contact with others. Hikari will often want to hug or hold onto Yuki due her cold body temperature since vampires don't manage well in the heat. Her favorite food is liver and onions. Afterwards, Hikari explains that she wanted to prioritise everyone having fun instead of going out of their way for her.
Volume 3 ranked 21st, selling 55,907 copies in its first week. Note: Won the DaVinchi x NicoNico Tsugi 2016 Manga Awards by taking 2nd place. This leads Himari to feel guilty about what she has done up until she realises that the superstition is actually false. After Sakie mentions her interest in Tetsuo, Ugaki points out that, contradictory to what she had previously assumed, Tetsuo was actually affected by her aphrodisiac but had acted like he was not affected so as not to hurt Sakie's feelings. Machi develops a crush on Tetsuo, due to his kind and caring nature. Hikari has a tendency to hang out in Takahashi's biology room since it's cool and doesn't receive much sunlight. Afterwards, Tetsuo ends up walking home with Himari, who has yet to trust him.
She will sometimes spread cold air while experiencing negative emotions and is susceptible to heat. Later, Kyōko finds herself in the biology prep room with an allegedly sleeping Tetsuo, unaware that he is actually awake. An television series adaptation by aired between January and March 2017. Despite being the older of the two sisters, Hikari acts as the younger, more child-like sister where as Himari acts as the more adult and mature one. After befriending Takahashi, Hikari, and Machi, she begins to open up about herself and talk more. The series aired on , , and between 7 January 2017 and 25 March 2017.
It dropped to number 14 for its second week, selling another 32,283 copies. He has guardian-like and caring relationship with the girls and is always looking after them for their well being. For this reason Sato lives alone away from civilization since she can't live in an apartment complex or any place where their may be a lot of people around. Later, Hikari sets Kyōko up on a practice date with Tetsuo, who carries her head around while Hikari keeps her body at her house. As Tetsuo struggles to talk with Sakie due to the measures she takes to keep her powers under control, one of his new students, a vampire named Hikari Takanashi, asks for his help in carrying the headless body of her classmate Kyōko Machi to the nurse's office.