The Acarr System was the former home of Clan Plagueis after the unification of Clans Exar Kun and Satal Keto. The clan lived here for half a year before the star started to go supernova. They left just in time, as the star exploded and destroyed the system for all eternity.
Acarr
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Sigil
The closest orbital to the sun, Siligan, simply named Sigil, is a massive gas giant that serves 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 is also the natural resting spot of the Terragots.
Eden
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 tropical sorroundings discourage visitors, as do the insects and animal life, but the Krath learned to keep these things at bay, and formed a relationship with the locals to get supplies in exchange for protection, despite the natives thinking of the dark jedi as demons.
After the planet was abandoned, Battle Team Exar's Shadow, led by Aabsdu, investigated it for any traces. While they found nothing useful to the clan, they did uncover remnants of the Crimson Tide, and eventually the capture of Alonzo Bodelle
Ysgard
Ysgard was a dead planet that use to serve as the capital planet when under rule of the Alvaak. During Clan Plagueis' rule, it was used as a mining colony for its ore and minerals.
Elysian
A desert planet, it was the homeworld of House Exar Kun due to its open plains perfect for flying. It was also full of silicon that was 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 discovered before they were forced to evacuate.
Haven
The former homeworld of House Satal Keto, Haven was perfect for training grounds and barracks. It provided plenty of food and other nessecities, and was perfect for Dark Jedi training. It was also clear of any terrible atmosphere, so it was easy to watch from the surface for invaders.
Byfrost
Being the furthest from Acarr, Byfrost was a frozen ocean world where all life existed beneath the ice. In order to breat, organisms had to break small holes in the ice, extracting oxygen from the water, or dieing. A single settlement existed on the surface that monitered 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 icey plains