I don't think starting as a paladin makes any sense for a dark urge character. This person doesn't remember anything, has a terrible past, but somehow carries the power of a vow with no memory of having made the vow? This kind of approach is dead on arrival, imo.
However, again imo, it makes sense for a dark urge character to take a vow somewhere along the course of the journey. To set aside the past and dedicate the future to a cause. I'd argue that the moment this happens should be of vital importance to the character and the vow.
