Dairuin fought in the Dagor Bragollach (Battle of Sudden Flame) under his captain Barahir. With the loss of the battle, he remained with a small band of men resisting Morgoth and thus became outlaws. He was killed along with the other outlaws in FA 460 save for Beren.
- The Silmarillion: Quenta Silmarillion, "Of the Ruin of Beleriand and the Fall of Fingolfin"
- The Silmarillion: Quenta Silmarillion, "Of Beren and Lúthien"