Koyomi, the main character of the story, is a third year high school student who is close to failing every class except math. Shortly before the first novel begins, he was attacked by a vampire during spring break, and became a vampire himself. Although Meme Oshino helped him become human again, there are several lingering side effects; he can see in the dark, his eyes turn red when he gets angry, and he heals incredibly fast and can recover from horrendous wounds within hours. He remains scared of morning sunlight despite the fact that it no longer has any negative effects on him. He started dating Hitagi at the end of Mayoi Snail. Other characters seems to speculate that Koyomi is a lolicon, particularly Mayoi and Hitagi. Koyomi is the only person who thinks that his family relationship is bad, while Karen and Tsukihi believe otherwise. Koyomi, Karen and Tsukihi's parents were also revealed to be police officers.
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