Elladan and Elrohir were the twin sons of Elrond and Celebrían, the elder brothers of Arwen, and so grandsons of Galadriel. Like their father they were Half-elven: the Appendices say that Elrond's children were also granted a choice of kindred, but they do not tell what the twins chose.1,2
In 2509 their mother was taken by Orcs in the Redhorn Pass while travelling to Lórien, and tormented. Her sons rode after her and rescued her, and Elrond healed her body, but she could find no more joy in Middle-earth and sailed into the West. After that the brothers rode often with the Rangers of the North and hunted Orcs, never forgetting what had been done to her.2,3
After the Council of Elrond they went out with the scouts who searched the lands for the Black Riders. In March 3019 they rode south with the Rangers to find Aragorn in Rohan, bringing a message from their father.4,5
The days are short. If thou art in haste, remember the Paths of the Dead.
They went with Aragorn through the Paths of the Dead and fought on the Pelennor Fields, and they were among the captains at the Last Debate.5,6,7
Sources
Citations name the chapter rather than the page, so they work in any edition. The colour of each note shows what kind of source it is.
- Published story The Hobbit and The Lord of the Rings as Tolkien published them.
- Appendices Tolkien's own appendices to The Lord of the Rings.
- Appendices The Lord of the Rings, Appendix A, I (i), “The Númenórean Kings”
- Appendices The Lord of the Rings, Appendix A, I (v), “Here follows a part of the Tale of Aragorn and Arwen”
- Appendices The Lord of the Rings, Appendix B, “The Third Age”
- Published story The Fellowship of the Ring, Book II, ch. 3, “The Ring Goes South”
- Published story The Return of the King, Book V, ch. 2, “The Passing of the Grey Company”
- Published story The Return of the King, Book V, ch. 6, “The Battle of the Pelennor Fields”
- Published story The Return of the King, Book V, ch. 9, “The Last Debate”