Ornessar and Katrandil were talking during the whole trip to Aragorn's Camp near Pelargir. The atmosphere there, though, was awe-inspiring. Anyway, it was time for open war. Ornessar followed Elladan and Elrohir, his leaders, while Katrandil followed Aragorn. It was time to retake Pelargir from the hands of the Corsairs.
Ornessar and the elves had made their way into the city through a secret breach. They went onwards with some other gondorian men and opened the West Gate of Pelargir so that Aragorn's s could enter the city, and they aided Aragorn indirectly until it was time for him to call upon the dead, for them to fulfill their oath.
Aragorn's mighty voice sounded throughout Pelargir.
"Now come! By Isildur, I call you!", he said.
The Men of the Mountain appeared and rushed at the Corsairs, causing fear in their hearts. The Elves then regrouped with Aragorn and his Army. Aragorn, after the battle was won, said that he counts the Oath of the Wild Men fulfilled, and now they could find peace. Afterwards, they all took the ships of the Corsairs and they all rushed to Harlond.