Aerin was the daughter of Indor who was closely related to Húrin Thalion of House of Hador. When the treacherous Easterlings invaded Hithlum as payment for fighting on Morgoth's side in the Nirnaeth Arnoediad, Aerin was cruelly seized by Brodda and taken to wife against her will hoping to produce an heir to legitimize his rule as Lord of Hithlum. She secretly helped Húrin's wife Morwen. She sheltered Sador, the former servant of Húrin and childhood friend of Túrin. When Túrin, son of Húrin, returned to Dor-lómin, he learned from Aerin that his mother had left Hithlum. He became angry and in his rage he killed Brodda. While being hunted to the death, one of Túrin's followers saw the Hall of Brodda on fire and guessed that she had set it, and she burned to death in the fire. Afterwards, the remainder of the House of Hador in Dor-lómin were now at risk of being persecuted even more cruelly then they ever were before.