"Researching Forbidden Knowledge" and getting locked up for it still makes you a criminal. Like if a scientist performs inhumane experiments, they get locked up in jail, they're a criminal.
I personally think, with his grisly research and intellect and what little theme we know of him so far, he'd make a good Shadowblade or w/e the magical rogue thing is, though you could consider leaving him as his default class.
