it does look dumb but i think he can't use magic against this guy because it would only multiply, since touching magic is the requirement for multiplying of the bird it ate. and i think he can't use revert on something that was poisoned by black magic unlike the beast girl's natural transformation which is not magic but a trait. but wow, they just shove the deaths of those bears like it was no one's business... at least give it more depth. or rather a lot of it is a bit rushed and lacking in depth which this manga needs. though the MC is actually selfish to begin with but because they are adding "Family Bonds", he is becoming weird in this story (specifically, one page is him being nice and the next one is him being selfish and it repeats on and on to the next page which is confusing to know which side of him is the genuine trait of his character).