Zyzek System Defense was a defense organization that protected the Unknown Regions' Zyzek system, where the planet Zyzek was located. In 18 BBY, Senior Captain Mitth'raw'nuruodo, core name "Thrawn," and Generalirius Nakirre, the respective commanders of the Chiss heavy cruiser Springhawk and the Kilji war cruiser Whetstone, engaged in a confrontation over Zyzek.
As Nakirre prepared his warship for combat with Thrawn, Zyzek System Defense sent two pairs of patrol ships smaller than the Springhawk to confront the two warships while requesting for them to stand down. The generalirius considered destroying the newcomers; however, as that would kill their crews, preventing their enlightenment to the Kilji religion, he decided not to destroy the patrol ships. Nakirre complied with Zyzek System Defense's request, resulting in the Springhawk and the Whetstones departure from Zyzek.
Zyzek System Defense appeared in the 2021 novel Thrawn Ascendancy: Lesser Evil, the final installment in Timothy Zahn's Thrawn Ascendancy trilogy.
Zyzek System Defense appeared in the 2021 novel Thrawn Ascendancy: Lesser Evil, the final installment in Timothy Zahn's Thrawn Ascendancy trilogy.