The beard-cloak motif appears before Malory's account of Rience. Geoffrey of Monmouth tells how Arthur had once defeated the giant Ritho, who wore a cloak made from the beards of kings and demanded Arthur's beard as an addition. Arthur recalls that earlier victory when judging another giant's strength. The resemblance helps explain the connection made between Rience, Ritho and the Welsh Rhitta Gawr, but it does not establish that every teller meant a single man with a continuous biography. Malory's Rience is a human king.

His messenger brings a demand for homage in the form of Arthur's beard. Eleven defeated kings have already supplied the trophies with which Rience has trimmed his mantle, and one place remains. Arthur answers that his beard is still too young for the purpose and rejects the claimed authority behind the request. He warns that Rience must instead submit to him or risk losing his head. A knight at court confirms that the challenger is both proud and formidable. The exchange is not merely a joke about appearance: it is a contest over submission.

Rience's forces subsequently enter Arthur's lands, burning and killing. Balin and his brother Balan seek an opportunity to serve the king against him. Merlin meets them in disguise, identifies their purpose and offers the counsel without which they are unlikely to succeed. He brings them to a wooded position beside the road, where they rest until near midnight. The planned interception depends on knowledge of the enemy's movements rather than a direct assault on his whole army.

Rience has left his host with an escort to visit Lady de Vance. Balin and Balan attack in the narrow way, wound him and scatter the remaining guard. The king asks them to spare him, arguing that a living captive can benefit them whereas a dead man cannot. They accept his surrender and place him on a horse-litter. Merlin reaches Arthur first with news of the capture, and the brothers deliver their prisoner to the porters before departing again.

Arthur questions Rience about the men who defeated him. The captive names the Knight with the Two Swords and his brother, and Merlin explains who they are. In this consulted Malory episode, Rience is not then shown kneeling upon relics, swearing a formal oath and receiving release. His capture is the clear conclusion of his personal adventure here. The separate threat made earlier by Arthur should not be expanded into a completed ceremony that this passage does not describe.

The war continues through Nero, Rience's brother, and King Lot. Their forces threaten Arthur near Castle Terrabil, while Merlin delays Lot so that the armies do not strike together. The ensuing battle belongs to the consequences of Rience's challenge rather than proof that he himself remains commanding in the field. Malory's narrative moves on from the captive king. His mantle survives as the defining image: a collection meant to proclaim mastery, undone when the ruler demanding another king's submission must ask two knights for his life.