Ohhhhh, you said Jyggalag. I know exactly who that is. I really can't see it because you'll become Hermaus's champion, which is obviously the opposite of what you want.

He will only address you as his Champion if you've also done the Discerning the Transmundane quest beforehand. Besides, Knowledge and Order don't seem too opposite to each other in my opinion.

I was thinking that. I was also thinking maybe trying to use the Black Books to gain wisdom so that he can try and "predict the unpredictable" since they defy logic.

That makes sense too.

Bump for a reply.

Like Batman says, "Criminals aren't complicated...you just have to figure out what they want." What'll the thieves guild offer that being a criminal elsewhere won't? Support, Influence through the Black Briars, maybe thrill seeking (though the guild seems a bit uptight for that).

Thanks Borom.

Also, a place to rest your head, fences, and camaraderie

A little thread resurrection here - maybe his parents were in the Legion, and he was raised in an Imperial city, not on a stronghold.  Maybe he's connected somehow, by blood, marriage, or legion association, to Ghorza in Markarth or Urag at the mages college, is traveling to see them for reasons family or otherwise. Maybe he was a comrade in arms of Rikke, or (more of a stretch) Ulfric and Galmar. Maybe he came to study smithing with Eorlund Greymane, in an effort to become the Smith to Surpass All Smiths. 

Accidental murder of an innocent? Discovering he was being manipulated by Daedra to believe that his lover/brother/best friend had betrayed him, killing them, and then finding out they were innocent? Accidental murder of a child? Being stuck in isolation, frozen into a Dwemer ruin for a decade before someone stumbles across him and releases him? Being tortured by the Thalmor? Being the Imperial soldier forced to deliver the wheelbarrow of Blades heads?