The only thing defective here is that dumbass party leader's head.
Seems like the mage knew Raust's value, or at the very least realized it after he left.
But the leader, holy shit.
Literally gets carried by Raust to the lower levels, can't even tell he was doing it because he was too busy getting hit by fucking everything like an idiot
Raust leaves, taking the team's value with him, still can't comprehend that he himself is actually a talentless hack