At Night, I Become a Monster (Novel‪)‬

Every night, Adachi transforms into a nightmarish creature--and every morning, he reverts to human form. When he encounters his ostracized classmate Yano Satsuki in his monstrous state, the two develop a peculiar bond. But daylight brings its own form of terrors. Which is worse, the monsters at night, or the cruel realities of the classroom by day?