I think it's worth pointing out that baptism isn't some sort of irreversible surgery that forever changes a person's character (like the capping process in The Tripods). It's just water and a few 'magic' words.
At the age of five, Skagra decided emphatically that God did not exist. This revelation tends to make most people in the universe who have it react in one of two ways - with relief or with despair. Only Skagra responded to it by thinking, 'Wait a second. That means there's a situation vacant.'