Dáin I was a King of Durin's folk, son of Náin II. Under Dáin I, attacks by dragons on their mines in the Ered Mithrin continued. Dáin I was killed by a cold-drake in 2589 T.A., and the Ered Mithrin were abandoned by the Dwarves. He was the last king of all Durin's folk. He was succeeded by his son, Thrór, who returned to Erebor and unsuccessfully attempted to reclaim Moria. He also had a younger son, Grór.