Le Casse Roi Russe, meaning the Castle of the Crimson King, is the residence and seat of the Crimson King, located in End-World next to Castle Town.

It is first seen during The Gunslinger Born when the Crimson King is contacted by Marten Broadcloak through Black Thirteen. It is later visited by Roland Deschain when he is trapped inside Maerlyn's Grapefruit where he meets the Crimson King for the first time and is asked to join his side.

Le Casse Roi Russe is seen again in The Dark Tower as Roland and Susannah Dean finally reach End-World. The castle's occupants, save for Rando Thoughtful, have all been killed by the now insane Crimson King. The King has also vacated his castle to wait for Roland at the Dark Tower itself. When Roland comes upon the castle, he is greeted by Thoughtful who pretends to be a shape-shifter, taking on the appearance of Stephen King. After Roland leaves, Thoughtful is killed and eaten by Mordred Deschain.