The Dolorous Stroke is a trope in Arthurian legend and some other stories of Celtic origin. Sir Balin left the court of King Arthur on his quest to avenge a knight he had failed to protect. Balin met another knight whom he befriended. Merlin met them in another disguise, revealing the identity of the invisible assassin was Garlon the Red, the brother of King Pellam. Merlin insisted that Balin should give up the quest or else bring sorrow and misfortune to Logres. Balin stubbornly refused to give up on the quest to avenge the unnamed knight he had failed to protect.