You're either worth my time...
The most important thing to bear in mind about Theo is that he has a fragmented mind. In fact, he has very little memory at all. He suffers from a kind of amnesia that has left him clueless of he once was. Underneath all of his sarcasm and bravado, Theo is truly worried about what exactly he was.
So who was he? Basically, one of the baddest guys in Mizahar: He rolled with a group of bandits going by The Avaric Flame. A cult of Ivak, they raped, murdered, and plundered to get by while searching for relics in the hopes of appeasing their formerly caged god. Theo's worries are, unbeknownst to him, rightly placed. Theo was going by Revan at this time and was an accomplished apprentice of a pyromancer and performed a litany of evil acts. The Avarics growing power, however, had placed them in the sights of other nefarious individuals, and through an act of betrayal, the group was destroyed.
It was in these acts that Theo lost his memory, and since then he has been hunted and manipulated by those who wish to extract what information he has. These pursuers have had varying degrees of success, but Theo has kept his guard up and has managed to thwart them thus far. However, this eventually all will have to come to an end.
But in the meantime, Theo remains on the run, hiding the best he can. There is a deep loneliness in this. Varying acts of escapism such as drinking and mercenary work often occupy his time. He knows that if he garners enough prowess, he can one day hope to confront his captors.
...Or you're not.