Therefore then Reynaud took the chess board and smote Berthelot upon his head so hard that he cloved him to the teeth. And thus Berthelot fell down dead to the ground afore him. This is a piece of medieval chess reporting. And raises the chess-board and gave him such a great blow with it that he dashed out all his brains and forced his two eyes out of his head, and he fell dead in the middle of the place. These quotes I take from the book Chess Pieces by Norman Knight, a fine anthology of chess-related literary texts.
Bones crack and blood spurts all over the place in medieval chess literature.
But these are not really acts of revenge. The violence is too spontaneous, too natural. Somebody loses a game, he gets angry and cleaves his opponent's head. That's the way things were. Like a lion who guiltlessly slaughters his prey.