Gweld was a red-haired witcher who appeared in the graphic novel Zdrada (English: The Betrayal), the 6th novel in that series. He was Geralt's best friend at the Wolf School.
Gweld and two other young witchers took a part in witcher trainee exchange which was part of the plans to make an emotional bond between witchers of the Schools of the Wolf and the Cat. This however turned to be Treyse's ruse during the Tournament when Gweld was forced to represent Cats in a duel against Geralt. Sensing the menace, he asked Geralt to tank the fight, which would stupify the Cats. Unfortunately, he was accidentally killed by his friend when Astrogarus was attempting to mind-control him in order to kill Geralt.