Koyomi Araragi (阿良々木 暦, Araragi Koyomi) is the main protagonist of the Monogatari series and the most frequent narrator. He is a third year high school student who survived a vampire attack during spring break, and barely regained his human life in the time that followed. Since then, he's been affiliated with Shinobu Oshino, the vampire that had attacked him, and continues to feed her his blood. As such, he's still not entirely human and certain vampire traits remain, such as regeneration.
He is voiced by Hiroshi Kamiya in the Japanese version of the anime, and by Erik Kimerer in the English version of the anime.