The Acarr System was the former home of Clan Plagueis after the unification of Clan Exar Kun and Clan Satal Keto. The clan lived here for half of a standard year before the star started to go supernova. They left just in time, as the star exploded and destroyed the system.
The Acarr System was first discovered during the beginning years of the Old Republic. It was found by a routine survey mission that had been sent to find possible avenues of expansion of the ever increasing population of the Republic. At first the system seemed promising to the explorers; it provided a blank canvas for them to terraform and populate as they wished. The plans for expansion, however, were cut short when the charting ship mysteriously vanished in the middle of a transmission. A follow up ship found the remains of the former ship scattered throughout the star system, along with the cause of its destruction: random ionic solar blasts. The yellow star of Acarr, it was discovered, was in the early years of transitioning into a red giant, and was releasing random bursts of ionic solar flares that wreaked havoc on both ships and guidance systems. To make matters worse, the flares had attracted the attention of space dwelling organisms later named Acarrian Terragots.
These creatures were as large as an average escort ship, and their natural habitat had given them armor just as strong. That, when combined with the radiation blasts the creatures emitted, made them highly dangerous. The Terragots were territorial and aggressive, and took offense to any intrusion into their territory. The plans for colonization by the Old Republic were scrapped.
Hundreds of years later, when the Dark Jedi Brotherhood split from the Emperor's Hammer, Sith Battlemaster Khan discovered that the system had gone unused, and set his sights on using the system to house his "fugitive" Clan Alvaak. The Terragots proved no challenge to Force sensitive Dark Jedi, and the Acarr System became the home of Clan Alvaak.
Years passed, and the system was given over to Clan Exar Kun. When the clan combined with Clan Satal Keto, the new clan, named Clan Plagueis, took over the system. They stayed here as long as they could, but they were forced to relocate when the star moved into its final stage and went super nova. Today, a massive black hole exists where the system used to be.
The closest orbital to the sun, Siligan, simply named Sigil, was a massive gas giant that served as a natural buffer between the outer planets and the radiation of the sun. This buffer failed, of course, when the star went supernova. It was also the natural resting spot of the Terragots, who were wiped out along with the system.
Eden is the former homeworld of House Bane, and was perfect space for the secretive, information gathering and hording house to store their knowledge of information. The untamed tropical surroundings discouraged visitors, as did the voracious insects and animal life, but the Krath learned to keep these things at bay. Though the natives believed the Dark Jedi to be demons, they forged a mutually-beneficial relationship with House Bane.
- Main article: Recapturing the Captured
After the planet was abandoned, Battleteam Exar's Shadow, led by Aabsdu, visited the planet, hoping to scavenge anything useful. Though they didn't find anything that could advance their cause, they did uncover remnants of the Crimson Tide. The information gained eventually led to the capture of Alonzo Bodelle.
Ysgard was a dead planet that served as the capital planet when under rule of the Alvaak. During Clan Plagueis' rule, it was a mining colony that produced large amounts of ore and minerals.
A desert planet, it was the homeworld of House Exar Kun. Its rich silicon deposits were mined for fighter fuel. Due to its central orbit around Acarr, it was also a perfect planet to house military in order to protect the system.
Battle Team Blades of Kun once investigated the planet after receiving a warning distress signal, but nothing was found before they were forced to evacuate.
Being the furthest from Acarr, Byfrost was a frozen ocean world where all life existed beneath the ice. In order to breathe, organisms had to break small holes in the ice or extract oxygen from the water. A single settlement existed on the surface that monitored all incoming and outgoing transports and vessels. When Clan Plagueis moved to the system, the planet was chosen as the clan capital for its privacy, and Castle Frost was erected on one of the large icy plains.