Looking back I saw a post about whether or not a good character could convincingly turn evil. I'm reminded of a quote from Spoony:
Actually, you know what? As cheesy as the acting is - and it is really, really fucking cheesy - I actually think Lords of Magick does a better job of building up Ulric's fall to the dark side than Star Wars did for Anakin. Oh yeah. I'm going there.
Here, let me lay down this beat, see if you pick it up: we like Ulric and we can tell he's a nice guy who loves his brother, but he's just weaker in mind and character. He's hot-tempered, impulsive, distracted by hot pieces of ass all the time, he's known to consorting with dark powers as shortcuts, and he's jealous of the powers that his brother has.
I'm not even kidding. In terms of a subtle, believable character arc of a noble, good-hearted wizard's fall to the dark side, The Lords of Magick is better than Star Wars.