Only I Know the Ghoul Saved the World, Vol. 1 (light novel)

While on her first foray into the Labyrinth, amateur adventurer Alice finds herself surrounded by ferocious beastmen. All seems lost, but she-s saved by a young man named Leon, who claims to be a monster himself. Alice believes there-s more to him than that, however. She thinks Leon might be exactly what this ruined world needs: a hero.