Éomer:

Second Marshal of the Riddermark, Éomer was born in the year 2991 of the Third Age. His father was Éomund, probably also a Marshal. Éomer had one sister, Éowyn. In the year 3018, Éomer encountered the Three Hunters, Aragorn, Legolas and Gimli, while out without Théoden's leave chasing a patrol of Saruman's orcs. He lent them two horses, Hasufel, and Arod, with the request that they return to Edoras, after their quest was completed or proved in vain. Thus it was that Aragorn, Legolas, and Gimli joined the host in the Battle of Helms Deep.

Before King Théoden died on the Pelennor Fields, he named Éomer as the next King of the Rohirrim. Éomer was unhurt throughout the rest of the War of the Ring, as far as the records say. After the crowning of Aragorn, Éomer swore the Oath of Eorl again with Aragorn, and always kept it until his death in the year 63 of the Fourth Age.