A good story, with some uniqueness maybe tie it into the Theran history or landscape somehow. Stick to it, roleplay it, live it. Make it known what your motivations should be....OR....keep them secret according to your role. **Note on Secret type roles and motivations---SOMEONE needs to know. Namely your god. So try and figure out a way to let that someone know.**

Now if you do all that, your role should be pretty good and solid. And you can buy your PBF at the end of your char's life and find out what we really think.