|Father||Lord Clement Piper|
A Feast for Crows
Lewys is named as a squire to Ser Jaime Lannister when Jaime takes command of a force to aid in the Siege of Riverrun. He names Jaime's horses Honor and Glory. Although Jaime usually does not name his horses, Lewys's choice of names makes him laugh and he accepts them. On route to Riverrun, Lewys collects blackberries and offers them to Jaime, who tells him to give some to his other squires, Josmyn Peckledon and Garrett Paege, as well as Ser Ilyn Payne.
Lewys is the only person who dares ask Jaime where his bruises, which are a result from his secret nightly sword training with Ilyn Payne, come from. Jaime tells him that they are love bites from the lusty wenches at Castle Hayford.
At Riverrun, Ser Daven Lannister recognizes Lewys from his looks as a son of Clement Piper. Daven tells Lewys that he beat his brother Marq bloody in a mêlée once, after Marq had taken offense at Daven's question whether the woman dancing naked on his shield was his sister. Lewys tells him that it is the sigil of their house and that he does not have a sister. Jaime tells Daven to leave Lewys be after Daven has suggested to Lewys that it is improper to hide behind a naked woman as it makes the attacker feel unchivalrous. When Jaime and Devan later discuss the lynching of Lannister foragers and Devan suggests that some lords of the Trident might be responsible, Jaime think to himself that he would hate to have to execute Lewys, the son of a riverlord, as he has grown fond of the boy.