Call of the Night, Vol. 8 By Kotoyama

Antisocial, dorky boy seeks fun-loving, sexy vampire for blood-sucking and transforming into her minion

A visit to the night school Nazuna attended years ago yields new insights into her forgotten past. Niko, her former vampire instructor, reminds Nazuna about her first friend, Kyoko. To aid in the investigation, Ko must pretend to return the affections of a boy-crazy student. Then, as more clues are discovered, a tale of friendship, betrayal, and murder unfolds...