Karin

Japanese Title: かりん

English Title: Chibi Vampire

Plot
Karin Maaka is the middle child in a family of vampires who immigrated to Japan two centuries earlier. Unlike the rest of her family, Karin does not feed on blood, she produces it. As a result, she is forced to bite others to expel the extra blood, lest she suffer exaggerated nose-bleeds. She also exhibits no normal vampire traits, and instead lives her life just as an ordinary teenage girl would. She can go outside during the day, attends high school, and follows the sleep pattern of normal humans. However, the general peacefulness of her life is disrupted with the arrival of a new transfer student, Kenta Usui.

Any time she goes near him her blood increases. At first she tries to avoid him but they are in the same class and work in the same restaurant. Kenta begins to think that there is something fishy about Karin and eventually he learns her secret. Karin's elder brother Ren tries to erase his memory but Anju, Karin's younger sister, stops him from doing so. She convinces their parents Henry and Calera to make Kenta their ally, because he can help Karin during the daylight. Karin and Kenta become friends, and as they spend more time with one another, fall in love, though they are slow to admit their feelings to one another.

Yuriya Tachibana, a human-vampire hybrid, moves to the area at the request of her vampire uncle, Glark. By chance, Yuriya gets a job at the same restaurant where Karin and Kenta work. As hybrids are sterile, Tachibana disapproves of Karin and Kenta's relationship, feeling any children they had would be unhappy like her. Despite this, Karin likes Tachibana and considers her a friend. On the other hand, Karin's grandmother Elda hates hybrids, as a betrayal danger to vampires. Karin rescues Yuriya from her grandmother. Karin is unaware that Tachibana is actually there to help her uncle and the Brownlick clan spy on her. After another nose bleed leaves Karin comatose for several days, Karin's family ask Kenta to stay away from her, but the two lovers are unable to stand being apart and eventually reunite and become a couple. Shortly after they share their first kiss, Tachibana helps Glark and Bridget Brownlick kidnap Karin and take her the Brownlick estate. It is revealed that Karin is a "psyche", a blood-giving vampire that can give life to other vampires and heals the sterility currently plaguing all vampires. In doing so, however, vampires have historically been greedy and drain the psyche dry, killing her as a sacrifice. The first psyche, Sophia, reveals herself to Kenta but cannot be seen by anyone else while helping Kenta find Karin.

Karin's father Henry, her brother Ren, and Kenta go to rescue Karin. Meanwhile, Tachibana is horrified to learn that not only will Karin be killed, but also raped until she has a child to produce a new psyche to replace her. She apologizes to Karin for disapproving of Kenta's relationship and for hurting Karin, and helps her escape just as Kenta comes in with Ren. While Ren takes care of the vampire, Bridget, holding Karin captive, Henry battles Glark and the Brownlicks, joined belatedly by his mother Elda. Kenta, Karin, and Tachibana escape, but Tachibana leaves them to go ensure her uncle won't be caught in the sun.

It is later revealed that Karin shared consciousness with Sophia, who gave Karin her condition and helped Kenta rescue Karin. Karin stopped producing excess blood (and being a vampire altogether) after Sophia moved from Karin to Kenta during her last bite. Karin's family sorrowfully erases all of her memories of them, so that she can live as a normal human with Kenta, while they quietly watch over her. They had prepared to do so for over four years, and the process is successful; they cannot erase Kenta's memories however without him reverting to a 4-year old such that he is left having to keep the secret from Karin, who he marries shortly after. At the end of the series, Karin and Kenta have a daughter named Kanon, who is the reborn Sophia; Karin's sister Anju continues to watch over her sister's happiness.