We killed this first ghost boss a few days ago, in super low gear on new chars, and think there might be a bug with him, he did zero damage, like not even 1 damage, and i think we had around 220ish armor only, not complaining! but that does seem unintended.
He is not alone, as mentioned in another thread I can’t find right now enemies which use weapons meant for player only (“corrupted“ buff) deal no damage. Also thralls equipped with this weapons.