An immortal companion of Yuta. She was raised by a group of old women that kept her captive and incapacitated in a hut. They were really mermaids that sought to eat Mana once she reached her adolescence to regain their youth. She travels with Yuta since, and possesses a large sense of loyalty and feelings towards him, but due to her somewhat naive and spoiled nature, she doesn't seem to truly realize that her emotions towards him are possibly love or just simple affection.
Ayaka Nikaido is the scheming president of the Second Newspaper Club. She considers the Student Council president, Kaori Shirakawa, her nemesis. She tries to expose Kaori's corruption with the help of her club members but this merely results in her getting on Kaori's bad side and repeatedly getting her club into trouble. It is Ayaka who pushes Yuuki Akamatsu into joining the Second Newspaper Club as a way of improving his social situation.
Anju is Karin's younger sister and she absolutely loves her, close to the point of obsession. She will do anything for Karin. She has not quite awakened as a vampire, causing her to be somewhat sensitive to the sun, and resulting in her only attending school on overcast days. However, she does have an amazing control over bats despite this. Anju is very reserved, speaking in a quiet manner and wears a Gothic Lolita attire. Boogie-kun is her companion, whom she carries around and is her favorite of her dolls, something she enjoys collecting. In the anime, Anju's blood preference is jealousy when she awakens. In the manga, it's loneliness.