Tokyo Ghoul Vol. 1 (manga)

Ghouls live among us, the same as normal people in every way--except their craving for human flesh. Ken Kaneki is an ordinary college student until a violent encounter turns him into the first half-human half-ghoul hybrid. Trapped between two worlds, he must survive Ghoul turf wars, learn more about Ghoul society and master his new powers.
Shy Ken Kaneki is thrilled to go on a date with the beautiful Rize. But it turns out that she's only interested in his body--eating it, that is. When a morally questionable rescue transforms him into the first half-human half-Ghoul hybrid, Ken is drawn into the dark and violent world of Ghouls, which exists alongside our own.