One of the band of men who remained and fought beside Barahir and Beren after the land of Dorthonion was overwhelmed by Morgoth. Dairuin was one of the last twelve survivors of Barahir's men, whose deeds in defiance of the occupying armies provoked Morgoth into action against them. The outlaws were betrayed by Gorlim the Unhappy, and Dairuin was slain with almost all the others by Tarn Aeluin. Only Beren, who was away from the outlaw camp at the time, survived the massacre.