Merlin's departure was for a purpose which he told not to the king. He well knew that King Lot of Orkney, Arthur's bitterest foe, was marching to join Nero with a powerful host, and foresaw that if they fell together on King Arthur he and all his army would be destroyed. The shrewd magician thereupon repaired to King Lot, and held him with idle tales of prophecy till Nero and his people were destroyed.
For between Nero and Arthur a vigorous battle was fought, in which many knights won honor and renown, while King Arthur with his own hand slew twenty knights and maimed forty. But Balin and his brother Balan, who came in during the fight, did such mighty deeds of prowess that all who beheld them said they fought like angels from heaven or devils from hell, while Arthur beheld their prowess with wonder and delight, and vowed that he owed to them his victory.
The combat, which took place at the Castle Terrabil, ended in the complete defeat of Nero, and the destruction of nearly all his host. Word of this disaster was brought to King Lot, where he lay resting with his army.
"Alas!" he said, "why did I let myself be beguiled? Had I been there no host under heaven could have matched us. That false prattler, with his prophecy, has mocked and befooled me. But what shall now be done? Shall we treat with Arthur, or is it wise to fight him with half an army?"
"His men are weary with fighting and we are fresh," said a knight. "Now is the time to set upon him."
"So be it, then. And I hope that every knight will bear himself in the fray as well as I, for it is no laggard's task we have now before us."
Then with waving banners and serried spears they assailed Arthur's weary host. But the Round Table Knights, with the aid of the two valiant brothers Balin and Balan, roused themselves vigorously to the fray, and bore all before them, so that only where King Lot himself fought did his host hold its ground. But where he battled in the van all his men seemed borne up by his valor, and not a knight met him but was overthrown or forced back by his prowess.
Then King Pellinore pushed through the press of knights and horses, and struck a mighty stroke at King Lot as he fought at the head of his host. The sword failed in its aim, but struck the neck of the king's horse, so that the wounded animal fell to the ground with its rider. Then Pellinore struck so furious a stroke that his sword cut King Lot's helmet in twain, and cleft his head to the brows, hurling him lifeless to the earth.
Seeing their king thus slain, all the host of Orkney turned and fled, and great was the slaughter in the pursuit. That day there fell in all twelve kings, who fought with Lot and Nero, and all these were buried in the church of Saint Stevens at Camelot.