The Sennex, also known as the Sennex Pirates, hailed from the Sennex system and engaged in the practice of slave trading. During the Galactic Civil War era, they were infamous as some of the most reprehensible pirates operating within the galaxy.
Before becoming a bounty hunter, Aurra Sing was once enslaved by them, sometime before the fall of the Old Republic. The pirates informed her that the Dark Woman had deliberately abandoned her, after which they sold her to Wallanooga the Hutt.
In 1 ABY, Jabba the Hutt, disturbed by their presence on Tatooine, dispatched his enforcers to harass the Sennex, reminding them of his dominance over the planet. Consequently, Ephant Mon employed spacers to assassinate five Sennex slavemasters and nine Sennex guards within their compound, and to erase all data from their systems. Despite this, a Sennex spy by the name of Romo Vax successfully infiltrated Jabba Desilijic Tiure's criminal empire. He was ultimately killed in his hideout by one of Bib Fortuna's underlings.
Meanwhile, Sennex pirates abducted the wife and daughter of a moisture farmer from Tatooine, holding them for ransom inside a cave. They were eventually freed by someone known as the Hero of Tatooine.
Near Anchorhead, the Sennex also operated a slave bunker disguised as a research facility. Huff Darklighter, fully aware of their illegal activities, tasked a spacer to disrupt their operations.
The 2003 video game Star Wars Galaxies, a massively multiplayer online roleplaying game developed by Sony Online Entertainment and published by LucasArts, featured the Sennex prior to its shutdown on December 15, 2011.