Kono Fukushuu ni Gyaru wa Iranaiこの復讐にギャルはいらない; Nemotode Meets Lion and....; 这场复仇不需要辣妹; I Don't Need a Gal for This Revenge

Nozomi Kashihara, a lonely hitman whose parents were killed, has never known warmth in his life. He betrayed the "family" that raised him and lived his life as a plain high school student, but after he saves a gal in his class from a group of delinquents, he somehow finds himself getting closer to her. Kashihara begins to suspect that she may be an assassin targeting him...