Firrhana was an Outer Rim planet once controlled by the Sith, who conducted sacrifice rituals in a they built there. It was abandoned after an ecological collapse caused by a volcanic eruption.
An ancient volcanic eruption rendered Firrhana almost uninhabitable, characterized by alternating fields of lava and fungi. The planet was abandoned in the aftermath, only a few hardy lifeforms managing to continue their existence. A Sith temple remained in ruins atop several blackened peaks in the middle of a lava field.
Firrhana was once a Sith world that housed a temple used to sacrifice victims in blood rituals before a volcanic eruption forced its abandonment. Centuries later, by the end of the Clone Wars, a bounty hunter named Jakadis had converted the temple into his personal fortress, where he imprisoned several Jedi he had captured. Having heard of this, the Grand Inquisitor tested former Knights Iskat Akaris and Tualon Yaluna by sending them on a mission to eliminate the Jedi. With the aid of a Purge Trooper, Akaris infiltrated Jakadis' defenses and proceeded to kill the three Jedi she found, taking their lightsabers as trophies. On her way out, she slew Jakadis and drank a toast in the temple's sacrifice chamber.
The Sith temple was the most prominent feature on Firrhana.