Raldbthar is an ancient dwemer ruin found on the slopes of the Pale, in the province of Skyrim. Built amidst the snowy heights of Shearpoint, Raldbthar was once a powerful city-state that served as the primary source for the blue crystal, Aetherium. It was one of four city-states in a pocket empire that spanned across modern-day Skyrim, led by the Kragen Clan of Arkngthamz. Raldbthar is one of four cities that contains a great lift to Mzark Cavern in the subterranean world of Blackreach.
Raldbthar was built by a clan of Dwemer that migrated to Skyrim following the Kragen Clan and formed a loose alliance with the aforementioned clan along with two other cities, Bthar-Zel and Mzulft, to harvest and use Aetherium. The city-state served as the main mining operation for the Aetherium, building a mine that ran deep into Shearpoint, where it would send the raw material to the Aetherium Forge at Bthalft in the wilds of the Rift. This alliance ended shortly after and each of the four cities waged conflict in what is known as the Aetherium Wars, as each city sought ownership of the Forge. The decades of battle had severely weakened the nations, paving the way for High King Gellir's conquest over the Dwarves, and the Dwarves of Raldbthar were forced out of their city. The Dwemer were able to return to their homes, but like the rest of their race, they disappeared, leaving behind whatever Aetherium they acquired. Raldbthar was subsequently sacked and later abandoned much like other Dwemer cities.
By 4E 201, the ruins were occupied by a large bandit clan led by the crime lord, Alain Dufont, who managed to steal a large sum of wealth from the Shatter-Shield Clan of Windhelm, including their family heirloom, the enchanted warhammer, Aegisbane. Dufont's streak of luck ended when he was murdered by the Dark Brotherhood for a contract from his former deceived lover. The Last Dragonborn traveled to this location and discovered a shard of the Aetherium Crest within the Deep Market of the ruins.