"just adopted a human child that seems stronger than an oni like me. UwU now I understand why my son likes humans UwU they are kind and strong and polite and will have a tea party with me if I offer cake."
Man, I almost started suspecting the tiny-head was just an oni-thing but then the humans have it too! This mangaka could probably use a good lesson on bodily proportions or something.
So no harem then? Hopefully author at least has the decency to stick with it, too many authors make rival love interests with 0% chance of actually overcoming the lead girl and that's always a dick move.