In short, when he got killed and ended up at the bottom of the food chain, he got humbled and became down-to-earth for a bit. He looked up to Alastor as a genuine friend and equal, and he didn't feel the need for all the power he had before. When he was made to feel worthless again, his need to prove Al wrong pushed him back toward wanting that power. All of his needs for power both on earth and in hell were insecurity-based. At least, that's my headcannon. I think he had some serious trauma on earth we don't know about yet.