Sweers was a knight who hailed from a family of Nilfgaardian nobles. Hired by the prefect of Amarillo to track down Ciri, he recruited a gang known as the "Trappers" to assist him. He wore a winged helmet. His family were the sworn enemies of the Varnhagen clan.
The knight was a middle-aged but still robust mam with a scarred face. When riding, he wore a helmet with birds' wings, but they were not the wings Ciri had first seen in her nightmares and later on the isle of Thanedd. He was not the Black Knight of Cintra. But he was a Nilfgaardian knight. When he issued orders, he spoke the Common Speech fluently, but with a marked accent, similar to that of the elves. However, he spoke with his squire (a boy not much older than Ciri) in a language resembling the Elder Speech, but harder and less melodious.
After finding Ciri in the Korath desert, the group's path was blocked by a knight in blue enameled armor, one of the Varnhagens. The knight and his squire were killed fighting the blue knight and never returned to Amarillo.