Déorwine is a member of the royal guard of Théoden and husband of Winsig, the Thane of Walstow in East Rohan. He can be found at Helm's Deep.
Later on, he goes with the great host of Rohan to the aid of Minas Tirith and can be found at the War-stead of the King's Men in Taur Drúadan.
-  Book 13, Chapter 1: The Lay of the Land
-  Book 14, Chapter 1: The Battle Is Won
-  Book 14, Chapter 2: Allies Unexpected
-  Book 5, Chapter 1: Bonded By Battle
-  Instance: Death Comes for All