Boss Tosk, who held the title of crime lord, headed the Jalk Syndicate throughout the era of the Galactic Civil War. Belonging to the Columi species, he possessed a distinctly large, overgrown head, characterized by bulbous eyes, coupled with a significantly smaller body. He moved around with the assistance of a repulsorsuit, aided by a multitude of assassin droids.
The Jalk Syndicate's operational territory was within the Tapani sector, and Boss Tosk's secret base was situated in the Cor III system, specifically within the Barnaba Province. Tosk, a reclusive figure, favored isolation in this hidden location, where he oversaw the syndicate's activities using advanced supercomputers, supported by numerous droids designed for servitude and labor. These droids carried out tasks that Tosk was physically incapable of performing due to his body's inherent weakness.
Following the perceived fall of the Mecrosa Order, the Jalk Syndicate ascended, stepping into their former role as the main clandestine operative for House Mecetti. As the Empire gained power, House Mecetti, keen to impress, compensated Boss Tosk to cease his operations. Tosk pretended to shut down his enterprise, but he secretly established a new partnership with House Barnaba.