Wulf was the son of Freca, who tried to force a wedding between Wulf and the daughter of the King of Rohan, Helm Hammerhand. Helm killed his father, and Wulf took charge of a Dunlending army that overran Rohan.
Portrayal in adaptations
In Middle-earth: Shadow of War, Wulf was depicted as forcing the marriage himself amd nearly killing Helm Hammerhand in the process. The wounded King took a Ring of Power from Sauron to restore himself and to march on Wulf's hall, where in his rage, he killed Wulf and, accidentally, his own daughter and all his soldiers. He was portrayed by Liam O'Brien, credited as "Daughter's Suitor."