That depends on how you play it.
In his 3.0 incarnation, working up from 1st through 21st level, he took levels of Templar (from Defenders of the Faith) when he was a guardian of one of Dumathoin's libraries. He eventually went apostate, and joined the cult of Ogremoch. In time, he defeated the Herald of Ogremoch, and took his place. In our realm, Ogremoch is a rising deity who was recently released and not very powerful. (This is laying the groundwork for the Temple of Elemental Evil, for those who haven't caught it - another one of the characters in the group is the Herald of Imix.) So not having to drain his power granting spells, and having a High Priest who was self-sufficient, was a bonus.
He's a neutral evil deity, in our pantheon, and the idea of stealing spells from other gods pleased him.
That's how we played it. Your mileage may vary.