Ruwas is a mentioned-only character in Horizon Zero Dawn: The Frozen Wilds.
History
Ruwas was a Carja hunter who came to the Cut in search of better hunts. He was likely a noble, given the price of his headdress and conversation with Rhavid revealing that Carja of means can typically afford to make such expeditions. According to Furahni, Ruwas's father was a soldier who died while aiding in the Liberation of Meridian.
He got into a fight with a Banuk hunter named Inatut after challenging the honor of the latter's werak. Ruwas managed to get the upper hand on the inebriated Inatut, but was killed shortly after by a group of Banuk bitter about the Red Raids. Before retreating, the killers stole Ruwas's headdress as a trophy.
As Inatut was the one to start the fight, he was framed for the murder. However, thanks to Aloy's investigation, the truth behind Ruwas's death was revealed, and Inatut was saved from his Banuk exile. Inatut would return Ruwas's headdress (which he got from Aloy) to the Carja outlanders.