I also thought that he doesnt seem very human to me.
Oh, so it's not just me! I actually thought the same thing! He seems very sus... Like, he even knows about the different magic and stuff like that. IDK, I just feel like he's the demon king. If not the demon king, I just think he's part of their community. Maybe even demon prince idk HAHAHAHAHAHA. But he is definitely not a normal companion.
Spoiler
He is the demon king. He wants desire to lift his island.
Ooh, yaaaasssssss! we were righttttt UWUWUWU
oh shoot, I forgot not to reply. now the spoiler is seen :')
Asukara, will he succeed? Or will he like get good or die or smth?
Spoiler
Desire will stay with him. He will eventually fall for the FL. But sadly he is just a 2nd ml. ML and FL will get married and visit him when they are old but sybil remains same as he is a demon. He will kind of remain alone with desire and demon by his side
I feel like Sybil will be the demon king(°_°)
But who knows.. this is only a theory NOT a spoiler.