Éomer, son of Éomund, is the current Third Marshall of the Riddermark. The nephew of King Théoden, he is second in line for the throne of Rohan, behind his cousin Théodred. As such, he also lives under the shadow of Wyrgende's curse.
His parents are Éomund of Eastfold and Théodwyn, the sister of King Théoden. While still a young man of just twenty-six, the King's nephew was made Third Marshal of the Riddermark, and took command of the Riders of Eastfold. The days of his youth were harsh ones for Rohan; its people were imperilled by Orcs out of the north, while a certain Gríma son of Gálmód, later found to be a spy of Saruman, gained influence over the King.
Éomer is still just twenty-eight years old. He will rule the Rohirrim for another sixty-five years, through which he maintains a great friendship with Gondor. Such was the plenty and peace of his reign that he will be given the surname Éadig, 'Blessed'. He will later wed Lothíriel of Dol Amroth, and will eventually be succeeded by his son Elfwine.
Éomer (East Rohan)
-  Chapter 1: Éomer
-  Chapter 2: Uglúk's End
-  Chapter 4: The Stone of Wyrgende
-  Chapter 5: South to Snowbourn
-  Chapter 6: No Retreat
-  Chapter 7: The Coming Tide
Éomer (West Rohan)
-  Chapter 8: Night Falls on Meduseld
-  The Last Great Stronghold
-  The Scattered Lords of the Westfold
Vol. III. Book 13
-  Chapter 1: The Lay of the Land
-  Chapter 2: Final Preparations
-  Chapter 6: Atop the Wall
-  Chapter 7: Defending the Deep
-  Chapter 11: Dawn Comes
Éomer (Far Anórien)
There Théoden meets his end, and grants Éomer the Kingship, first of the Third Line of the Kings of Rohan.
Vol. IV. Book 5
-  Chapter 7: Through the Stonewain Vale
-  Chapter 8: The Ride of the Rohirrim
-  Instance: The Ride of the Rohirrim
-  Introduction: Anórien (After Battle)
-  Instance: Death Comes for All
-  Book 6, Chapter 4: The Foe Resurgent
-  Book 6, Chapter 5: The Black Ships
-  Book 6, Chapter 6: The Battle Rages
-  Book 6, Chapter 9: The City Stands
-  Instance: The Hands of a Healer
Éomer (The Wastes)
Having now succeeded his uncle, Éomer King leads the Rohirrim of the Host of the West to the edge of the Wastes. He can be found at the Camp of the Host, preparing for the final part of the march to the Black Gate.
-  Remnants of the Éothéod
-  Instance: The Black Gate
-  Book 8, Chapter 6: The Drowning Tide
-  Instance: The Eagles are Coming!
After the battle
- "Stand and fight, soldiers of Rohan!"
- "Die, monster!"
- "I will fight for as long as I must!"
- "It is nothing. I can barely feel the pain."
- "I am fine. It is the merest of scratches."
- "Pay no heed to my arm. I am fine."
- J.R.R. Tolkien, The Lord of the Rings, Appendix A, "The House of Eorl", "The Kings of the Mark"