The trick to rising in Asmodeus's hierarchy—according to Castigo Carrera, at least—is to get the message when your superiors lecture you about things. He used to think he was worthless to his Lord, destined to wither away as a first- or perhaps second-circle cleric Creating Water for a village. But when his seminary instructor explained that this belief wasn't useful, he thought to himself, and determined... well, perhaps he was nigh worthless, but the rest of the Asmodean Church was worth just as little, and certainly he ought to take pride in being better than that. It was then that he knew he would rise high in the tyranny.

Given that he was going to raise high in the tyranny, one can infer that Castigo must somehow get himself into enough danger to level. So that's why he's still been fitting some adventuring into his schedule: he hasn't lately been assigned to the Worldwound, so he's certainly not going to win any more circles from fighting demons.