Count Alier was a lord of sufficient power to raise a private army and sufficient ambition to turn it against a neighbour who had done him no visible wrong. His domain lay somewhere in the borderlands of Arthurian Britain, near the forest of Broceliande where enchantments were common and the rules of ordinary warfare did not always apply. He was not a giant like Harpin of the Mountain, nor a sorcerer like the sons of evil at Pesme Avanture, nor a traitor like Mordred. He was simply a knight with more soldiers than scruples, a man who saw weakness in Lady Noroison's holdings and decided to take what he could by force. His methods were direct: he burned fields, plundered stores, and laid waste to everything that could not be carried off, pressing his attack until the people of Noroison armed themselves in haste and prepared to defend their castle to the last.

The defining encounter of Alier's life came on a Tuesday, when his forces advanced against Noroison in full array. He did not know that the lady had recently found a naked madman sleeping under a tree in the forest, that she and her maids had bathed him, shaved him, and anointed him with a magic ointment created by Morgan le Fay herself, the sorceress queen who was Yvain's own mother. The ointment had restored the knight's wits, and the lady had given him armour, a steed, and a cause. When Alier's army approached the narrow pass before the castle, Yvain charged against the mass of them with a fury that seemed to come from the madness he had only lately escaped. He struck one knight so hard that the man's heart burst and his spine broke, toppling both horse and rider in a single blow. He felled four brave knights in quick succession, and the men who fought beside him took fresh courage from his example, standing their ground against an enemy that had seemed unstoppable only moments before.

Alier watched the battle from the field until he saw that his cause was lost. Rather than face Yvain in single combat, he turned his horse and fled, feigning a wound to explain his retreat to any who saw him. But Yvain was not deceived. The knight pressed hard on the heels of the fleeing army, pursuing them through the pass and across the open country until the dead and the living stumbled together, horses disembowelled and men struck down from behind. Alier rode for the high hill fort that was his own stronghold, hoping to reach its walls before his pursuer caught him. He did not make it. Yvain found him at the foot of the hill, near the entrance to the fort, with not a single retainer left to stand between him and the man he had tried to destroy.

The surrender was as complete as it was swift. Alier had no way to turn, no room to resist, and no hope of escape. He yielded to Yvain and accepted his surrender, handing over his helmet, his shield, and his naked sword. Yvain led him back to Lady Noroison as a prisoner, and the lady came out to meet them at the head of her household, her delight at the reversal plain for all to see. She told Alier her demands, and he acceded most willingly, swearing by his faith that he would live in peace with her, restore every loss she could prove and more besides, and rebuild wherever his burning had caused need. He gave his word and his pledge both, and the oath was sealed upon his naked sword. Then Yvain, having refused the lady's offer of marriage and her offer to become his mistress, rode away in search of new adventures, leaving Alier to keep the peace he had sworn or break it at his peril.

Count Alier disappears from the story after that Tuesday, his name never mentioned again in the romances of Yvain or in the wider Arthurian tradition. Unlike the giant Harpin, who died by the lion's claws, or the false seneschal who burned on the pyre he had prepared for Lunete, Alier survives his defeat and is never heard from again. This silence is itself significant: he is not important enough to kill, not wicked enough to destroy, and not honourable enough to remember. He is one of dozens of minor antagonists who populate the margins of Arthurian romance, the local lords who make war on their neighbours until a knight of the Round Table happens to pass through and set things right. His legacy lies in the contrast he provides to Yvain's greater adventures, the small-scale villainy that reminds the reader how much the world needs knights who will defend the weak, even when those knights are themselves broken men fresh from the wilderness.