Ok this is just hentai at this point, I mean at first it was plausible having only one slave, but now its clear that the author is trying to satisfy both busty and petite lovers, its just gonna be more and more porn from this point onwards and its really boring
@Bwoo7072 she is the human they captured in the first chapters, she was one of the assassins I believe she is the head of the city they conquered when he first came into the world.
He never had to fight continuesly for longer than 5 seconds against a monster (he considered that blue hair guy a human). After a certain amount of time he got back to how he was in the rock mountain because it was familiar for him. And then dude went berserk