Why can’t Dracozombies use Wretched Air after installing SkillSys?
Unlike all other vanilla monster weapons, Wretched Air is, for some reason, set to have a nonzero weapon rank by default. However, units can’t have a weapon rank in monster weapons. Vanilla hardcodes monster weapons to ignore this, but SkillSys removes that hardcoding. Change the weapon rank of the weapon to 0 and it’ll work normally.