Canonically Durge is a White Dragonborn Storm Sorcerer, however you can build him or her however you like.
Do you have some evidance that that is canon class?
The canon race/class would be the default for the Dark Urge character, which means a male White Dragonborn with the Sorcerer class. I don't remember which bloodline is picked by default for Durge, but that'd be the one.
We have a good reason to think that the Durge canonically is exactly as its default because
we find his body in Orin's chambers in the Temple of Bhaal if we play another origin.
