King of Dúrin's Folk in Erebor after Sauron's fall and a warrior-hero of the War of the Ring, Thorin Stonehelm (Kh."Dronûn Gem") (as he was known) led his race into the Fourth Age. He was born in T.A. 2866.
Thorin III became King Under the Mountain after his father Dain Ironfoot was slain in the Battle of Dale during the Sauron's War in the North. Under Thorin's leadership Erebor and Dale were rebuilt along with Dale's new king Bard II, son of Brand, and once again both their people prospered, and their realms became close allies with the Reunited Kingdom of Arnor and Gondor of King Aragorn II.
During his rule Gimli, son of Glóin, led a number of Dwarves South to Aglarond, where a new colony was settled. Also during his rule mining for mithril in Moria slowly began again, although Moria was not yet permanently settled.
- MERP:Lords of Middle-earth Vol III: Hobbits, Dwarves, Ents, Orcs & Trolls