Born in the Spine of the World, Dorn fled to Luskan with his human mother when a rival tribe annihilated his father's savage people. In that northern city, Dorn's ruthless strength soon won him a deadly reputation and the attentions of a band of mercenaries whose wickedness exceeded even Dorn's. Imprisoned for the crimes of the entire group, Dorn made a fiendish bargain granting him even greater power and the promise of revenge.
A Blackguard of few words, Dorn is only too happy to ally himself with Gorion's ward and cut a bloody swath across the Sword Coast with his black greatsword, as long as that path continues to lead him to the traitors he has sworn to destroy.
(Blackguard Innate Abilities)
The Friendly Arm Inn, first floor, to the right of the entrance as you're walking in. (AR2300) (BG1 World Map) If you wish to add him right away: Heed Gorion's instruction about what to do if you become separated from him, speak with Dorn, and then proceed with the game's plotline to the south of Candlekeep.