I'll be Ryan, a Breton Theif, who dabbles in magic due to his natural abilities. He started off training to be a true Mage, but turned to a life of crime due to his parents dying when he was only 15. To survive he travelled city to city, town to town, conning and stealing as he went. He would befriend mages at local guilds, and learn from them all he could. Eventually he makes his way to Skyrim, where his past actions finally catch up to him, and he's thrown in jail.
That's my back story, and I'm sticking to it !
When I do get out of jail, I'm cling to join the mages guild, and by day I'll be known as an up and coming Mage, with high expectations in the guild. At night I turn to my true calling, and love, theivery. At some point I'll join the theives guild, because theyve heard of my legendary heists, and would be honored if I joined.
Then I'll obviously play quests, join as many guilds as I'm able, but I'll try to stick as close to my two faced/secret life character as I can. Perhaps I'll turn evil, or maybe I'll end up becoming a true heroe. It's gonna be a blast either way!