The Sif represented a unit of hired soldiers, or mercenaries, brought together by Erran Sif in the era of the Galactic Civil War.
Following the events of the Battle of Yavin, Erran Sif, previously an Imperial spy, became a target for both the Empire and the Rebel Alliance because she sold intelligence to the Hutts. Consequently, she escaped Corellia and went to Talus, where she formed her band of mercenaries.
This mercenary group, the Sif, operated from a bunker situated in the Akazi Plains. The group's members included several Trandoshans and Erran Sif's own siblings, Hirsch and Doak Sif. The Sif were actively fighting against both the Empire and the Rebels, while maintaining an alliance with the Hutt clans.