If 'partner' is the business sense and not relationship sense its possible that Tree Dorman was Amaya Blackstone's brother mentioned in the KQC5 transcript. Gwendolyn comments that Amaya didn't need a partner, she was a strong woman by herself. She believed Tree Dorman was underdeveloped. It is not known if Tree Dorman was a false memory thought up by the elderly King Graham, erroniously recalling him as Amaya's partner and another blacksmith, or simply a 'non-important' part of Graham's history, that was left out of his previous stories (since he didn't add anything to the stories).