The Irish try to make peace and build a house to entertain Bran but hanged a hundred bags inside, supposedly containing flour but were really housing armed warriors. Efnysien, suspecting a trick, scouted the hall and killed all the warriors by smashing their skulls. Later, at the feast, Efnysien murders Gwern by burning him alive and, as a result, a battle insued. Seeing that the Irish were using the cauldron to revive their dead, he hides among the corpses and is put into the cauldron by the unwitting enemy. He then destroys it from within, and kills himself at the same time. It is said that only seven men survived the battle, including Manawydon and Taliesin, Branwen having died of a broken heart. They were told by a dying Bran to cut off his head and take it back to Britain. It is said that Bran's head is buried with his head facing France where the Tower of London now stands.
It is possible that Bran is the origin of the headless horse man myth.