The Grumani temple chamber was located within the Morbollon Mesa on Skarpos. Prior to the Republic Dark Age, it was used to hide the Helm of Ieldis, an ancient Sith artifact created by Sith Lord Ieldis which was capable of driving sentient beings into a homicidal frenzy. The temple chamber had been built by the Grumani Hierophants, a religious sect.
In 1037 BBY, Aron and Mercia Holt discovered the chamber while on their quest to locate the Helm. In an attempt to deny the Helm to the Sith, they detonated the chamber with explosives; killing themselves. Before their deaths, they left a holorecording explaining their motives and actions. However, the Helm survived due to its dark side powers, and it was subsequently recovered by Sith Lord Odion in 1032 BBY. He attempted to use the Helm to initiate a Force-induced galactic apocalypse but was thwarted by Jedi Knight Kerra Holt and her former general, Beld Yulan.