Knowing that it was either Saruman's terrible wrath or that of Théoden that awaited him in the end, Wulfgar instead consented to a pact with Isengard, wishing to ensure the safety of his own kinsmen. However, the king was forced to reconsider his stance after discovering the devastation of Théodred's army in the aftermath of the First Battle of the Fords of Isen - carried with a considerable backing from the wildmen of Dunland. Alarmed, however, by the potential threat of Isengard, Wulfgar rushed with his army towards Edoras to unite with Théoden against Saruman. He soon began receiving tributes from the fallen Istari Saruman, though he refused to throw in his support behind the latter's master, Sauron, or the wizard's own duplicitous designs. He was a noble leader and content with the current situation of his people and rather sought to keep the uneasy peace between his people and King Théoden's.
Wulfgar was the king of Freca's folk who resided in Wulfborg, capital of Frecalund.
He could march his men back home, where they would be left to await either the wrath of Saruman or that of Théoden, who would surely come for him, having seen wildmen in his enemy’s ranks." - The Age of the Ring Lore Compendium He could march to Isengard and lay siege to it, but he would have no hopes of winning: the Ring of Isengard was wide, Saruman likely outnumbered him, and even if he had the advantage, he had no means to sustain his army. They would blame him for the atrocity that occurred there, and would take up arms against his men. "What choice was there now? If he remained, the strawheads would not hear his words.