Leaf is a monster who lives in a monster village. These monsters are carnivores and they eat humans (and each other.) But Leaf doesn't eat humans, because he wants humans to like him.
Sometimes Leaf disguises himself as a human. He doesn't do it because he wants to be human - he knows he never can be - but he doesn't want the humans to be disturbed by his presence.
Recently a human fell in love with him, and now he doesn't know what to do.