Koi wa Ankoku.

Sosei Takarai just wanted to be a regular high schooler. He goes to school every day, hiding a job he doesn't even enjoy, until the class idol, Asumi Shiramori, inexplicably asks him out. Sosei is over the moon, but with all his free time after school and on weekends taken up by his job, he barely gets to see Asumi, let alone go out on dates with her. Then one day, he spies his mysterious classmate Kuchina Hitsujimoto at his workplace. Why is she there? Sosei, after all, is as an assassin. His romantic entanglements are bittersweet and painful, and the closer Sosei gets to his dream of normality, the further away it seems. A dark rom-com about a boy who kills and a girl who takes lives with a touch. (Source: Yen Press) Note: After the cancellation, the writer continued and completed the work as a Web Novel on the Kakuyomu website.