Kalakar Six, found in the Outer Rim, was a volcanic satellite orbiting Dromund Kalakar. Its surface was characterized by extensive lava flows, and its crust was permeated by numerous magma tunnels.
This moon, Kalakar Six, possessed a Dark Side nexus and was once under the control of the ancient Sith Empire. It shared a system with Dromund Kaas, which housed the Dark Force temple belonging to the Prophets of the Dark Side.
During the period of the Cold War, the remains of an ancient settlement were unearthed, preserved due to the protective layer of ash from a volcanic eruption.
Legends suggested that around 100 BBY, the moon's inherent dark side energy drew the attention of Baron Yorn and his followers from Coruscant. They established a fortress there with plans to perform experiments. However, a subsequent supply vessel discovered that everyone except Yorn had disappeared. Yorn himself had descended into madness, having gouged out his own eyes and removed his tongue.
Shortly before the Battle of Yavin, Darth Vader journeyed to the moon, attempting to intercept Rebels who were supposedly carrying the Death Star plans. The Rebels were not present; instead, Vader had been deceived and drawn to the moon by local darksiders who pitted him in combat against a counterfeit version of Darth Maul. Vader ultimately defeated and killed the false Maul. Soon after, Darth Sidious arrived on the moon aboard a shuttle. He eliminated the darksiders and retrieved Vader. Vader suspected that the entire event was a test orchestrated by the Emperor, a claim his master refuted.