Yaki Rafiberg was a dwarf and an avid gwent purist who showed up to protest at Count Martin Monnier's tournament due to Martin trying to introduce the Skellige deck. If Geralt defeated the 3 previous players, he would then get to play Yaki, who uses the Scoia'tael deck. Yaki was also a friend of Zoltan Chivay.
Blood and Wine expansion
In the second expansion to the game, Yaki is present at Count Monnier's gwent tournament at the Pheasantry in Beauclair. He, and a crowd of other gwent purists can be seen protesting outside the entrance to the inn against Count Monnier's introduction of the Skellige faction, and their shouting can be heard as Geralt enters the tournament and is introduced to the other participants.
Later, Yaki and his crew get into the private area where the tournament is being held, and engage in a fistfight with Geralt and the other participants. After Geralt finally defuses the situation, Yaki agrees to play the tournament's winner in order to test the new gwent faction's worth using the Scoia'tael deck. If Geralt was eliminated in one of the previous rounds, Yaki and Count Monnier play, which results in Monnier's victory, otherwise, Geralt and Yaki play in the final.