@Reikou
the fight was probably just that engaging but the dragons' weren't as engaged as the others (demons like fighting, and MC's friends were worried about him)
it's also possible that targ's teleportation makes him hard to notice by sight/sound, but the dragon (with the best nose around) smelled him
@Clad95150
it's not about intelligence but values, demons just value strength that much. it's obvious that they don't really care that someone killed raisoku (and was trying to frame the humans) https://mangadex.org/chapter/658954/3
@Edjan
if you didn't like MC's methods, you probably should have dropped this early, it's clear from the first arc that MC needs tricks/better equipment to win against higher level fighters, because, since he's only a teenager he's not strong enough yet