Now Merlin arrives and reveals the history of the sword. The damsel who brought it once loved a knight who was slain by her brother. She took the lover's sword to the Lady of Avilon and asked her help. With witchly whimsy, the Lady of Avilon sealed the sword in the scabbard so that only the best and hardiest man in the kingdom would be able to draw it, and with it he would slay not her brother but his own. Merlin reprimands the damsel for bringing the sword here, knowing its curse.
Launceor of Ireland now sets out after Balyn. They fight, Balyn kills him by accident, and Launceor's lady takes his sword and brandishes it. Balyn tries to get the sword away from her but cannot without hurting her wrist. When he lets go, she kills herself with it. Balyn is shocked and grieved at this needless waste and hurries away. He meets his beloved brother Balan, tells him all that has happened, and agrees to let him join the hunt for King Royns. A great king comes by and asks who killed Launceor. Balyn tells him and the king predicts that Launceor's relatives will want vengeance. The king reveals that he is King Mark (a vicious double-dealer later in Malory), then encamps to bury the bodies as befits their station.
Merlin appears and tells King Mark that in this burial spot will one day be fought the greatest battle ever fought between two knights who dearly love one another — Launcelot du Lake and Tristram. Merlin will not tell Mark his name, but on the day Tristram is taken with his lady, then Merlin will give both his name and news King Mark will be sorry to hear. Then Merlin tells Balyn that because he let this lady die (though he could not prevent it) he is fated to strike "the Dolorous Stroke," a stroke more terrible than any but that which killed Christ. Balyn does not believe him. If he thought he were capable of such an act, Balyn says, he would kill himself on the spot. Merlin vanishes. Balyn and Balan take their leave of King Mark, Balyn identifying himself as The Knight with the Two Swords.
