The Zyzek system was situated within the Unknown Regions. Located within this star system was the planet of Zyzek, a prominent hub for trade among various nations and species situated east and southeast of the Chiss Ascendancy. Protecting this system was the Zyzek System Defense organization.
In the year 18 BBY, Zyzek's orbit was populated by a number of merchant vessels and warships, including the Kilji war cruiser known as the Whetstone and the Chiss heavy cruiser named Springhawk. These cruisers became involved in a confrontation that was brought to an end by the Zyzek System Defense, which resulted in both the war cruiser and heavy cruiser leaving Zyzek. The Springhawk's commander, the Chiss Senior Captain Thrawn, later theorized that the Watith Captain Fsir, who had previously ambushed the Springhawk before the altercation with the Whetstone, had been secretly hired to do so by the Grysk agent referred to as "Jixtus"—an arrangement that Fsir was unaware of—at Zyzek.
The Zyzek system made its debut in the 2021 novel titled Thrawn Ascendancy: Lesser Evil, which represents the concluding installment of Timothy Zahn's Ascendancy Trilogy.