|The title of this article is conjecture based on information revealed in the A Song of Ice and Fire novels or related material and may be subject to change.
- "When a new army of Green loyalists marched up from the Reach and laid siege to the city of Tumbleton, Rhaenyra sent two of her dragonseeds to lay waste to them. Instead, the dragonseeds proved their bastard nature and betrayed her."
- ―Viserys Targaryen
Ulf was one of the Targaryen bastards from Dragonstone recruited as a dragon-rider for Rhaenyra Targaryen due to his heritage, and rode the dragon Silverwing. After Aegon II's loyalists besieged Tumbleton, Rhaenyra sent Ulf and fellow dragon-rider Hugh Hammer to relieve her garrison. However, the two instead burned Rhaenyra's troops and defected to Aegon's side, drinking and whoring with his troops after taking Tumbleton.