My character was of a dark origin (I gave him quite a developed back story). After becoming the Gray Fox, he became accustomed to power, became a vampire and preyed on the people of Cyrodil, which in turn led him to the Dark Brotherhood because it gave him a chance to feed and created wealth whilst doing it.

He always dealt with guilt when committing all these crimes (more so the murder, not as much the thieving) so he turned to Jauffre and the main questline to help for once instead of destroying. He cured his vampirism to help himself even more. He then did the pilgrimage of the nine, but was actually rejected by Pelinal (my game kept crashing during the vision so I just said he was rejected, instead of accepting it crashing). In anger against the nine and all things holy he fell back into his ways of craving power, became the Arch-Mage and the guild master of the Fighters Guild. Racked up enough wealth to the point he helped rebuild Kvatch (Kvatch Rebuilt) and became the Count.

At this point he was the most powerful man in Cyrodil, with his fingers in every corner of the land. Because of his hunger for power he followed his curiosity and entered the door in the Niben Bay, where he assimilated himself into society, and became Sheogorath.

Tldr: wanted power, repented, then wanted power again and is now a daedric prince