Koi wa Ankoku.

Sousei Takarai, who wanted to be a "normal" high school student, has a secret side as an assassin. Asumi Shiromori, a cute but "normal" classmate, fell in love with Sousei at first sight, confessed her love to him, and became his girlfriend. Then there was Kuchina Youmoto, another slightly odd classmate who was always alone. Their intertwined love affair is sweet, bitter, and sad, and the "normal" they sought was so near and yet so far. The dark tale of a girl who always kills the people she touches, and a boy whose "lives remaining" increases with the number of people he kills, begins at school. (Source: MF Bunko J, translated)