Jok Donassius was a male human who held the rank of Fleet Admiral within both the Imperial Navy and the Imperial High Command of the Galactic Empire. Throughout his service, he exercised authority over Admirals Durril, Kinshara, and Thrawn, along with their corresponding task forces.
In the time leading up to the battle for Botajef, Jok Donassius, a male human, occupied the military rank of Fleet Admiral in the Imperial Navy and Imperial High Command of the Galactic Empire. This was around the time Governor Quesl and the inhabitants of Botajef announced their secession from the Galactic Empire. As the insurgency began, Admiral Donassius used a hologram to contact Commodore Thrawn of the ISD Chimaera, tasking him with resolving the situation, ideally through diplomatic means, but if necessary, through complete destruction. After Donassius and Thrawn concluded their discussion, Thrawn instructed Commander Karyn Faro to order the helm to set a course for Botajef. Following Thrawn's triumph at Botajef after a short battle and Quesl's independence attempt being revealed as a ploy to steal valuable artwork, Thrawn instructed his aide, Lieutenant Commander Eli Vanto, to notify Imperial High Command that the situation had been resolved.
Subsequent to the battle of Botajef, Thrawn received a promotion to admiral and was given command of the Ninety-Sixth Task Force. Shortly after this assignment, Thrawn and Vanto, his aide, were summoned to High Command headquarters for a briefing concerning the Batonn sector insurgency. Upon their arrival, Donassius stood on one side of the holoprojector, with Imperial Security Bureau Colonel Wullf Yularen on the opposite side, and initiated the introductions. He presented Admiral Durril of the One Oh Third Task Force and ISD Judicator, as well as Admiral Kinshara of the One Twenty-Fifth task force and ISD Stalwart, before introducing Thrawn and his [task force](/article/task_force]. Following this, Donassius introduced Governor Restos of Batonn, Governor Wistran of Denash, Governor Estorn of Sammun, and finally Governor Arihnda Pryce of Lothal.
After Pryce and Thrawn, who were acquainted, acknowledged their reunion despite the circumstances, Donassius remarked that the officials were brought in to address those very circumstances. He then instructed everyone to take a seat and for Colonel Yularen to begin the briefing. During the briefing, Governor Restos pointed out that while four planets were affected, there were only three task forces, inquiring about which star system would be neglected. Donassius clarified that the insurgency on Lothal was already being managed by Admiral Kassius Konstantine and his sector fleet, and that Governor Pryce had requested to participate in the Batonn sector situation as an observer, due to its proximity to Lothal and their similar circumstances.
Following Yularen's continuation of the briefing, which included details of the Batonn insurgency and Thrawn's assignment to the mission, Thrawn and Durril began a debate regarding the optimal strategy for defeating the Batonn insurgents. When Thrawn requested additional time to devise a better strategy, Admiral Donassius countered that time was of the essence, as each moment the Imperial garrison remained hostage further damaged the Empire's reputation. Donassius insisted that Thrawn immediately neutralize the insurgency by destroying [Scrim Island](/article/scrim_island] on the planet's surface, but Thrawn argued that doing so would result in the death of the hostages and reiterated his need for more time for reconnaissance and planning. After a brief pause, Donassius stated in a terse tone that, due to his discomfort, Thrawn would be reassigned to deal with the Sammun insurgents if Thrawn preferred. Thrawn then replied that he would go wherever the Imperial Navy directed him. After confirming that Thrawn's task force was ready for operation, Donassius assigned Admiral Durril and his task force to handle Batonn. Donassius then instructed Yularen to resume his briefing.
Following the briefing, Thrawn instructed Commander Karyn Faro, a leading officer in his task force, to personally lead the task force to Sammun and provided her with instructions on how to defeat the Sammuni. He also requested that the Shyrack be detached for his use, as he and Vanto had an errand to attend to. When Vanto pointed out to Thrawn that they were venturing into dangerous territory since Donassius had ordered them to Sammun, Thrawn countered that Donassius had instructed his task force to deal with the insurgents, but had not specified anything about Thrawn and Vanto themselves. The pair then utilized their light freighter, the Slipknot, to observe the battle of Scrim Island from a distance and establish contact with Nevil Cygni, the leader of the sector's insurgents.
Donassius would be compelled to reassess his initial disapproval of Thrawn's stance after Durril's failure to seize Scrim Island. In the subsequent holographic after-action meeting with Admirals Durril, Kinshara, and Thrawn, with the latter two reporting the successful completion of their assignments, Donassius was noticeably impressed with Thrawn, particularly for achieving success without even being present with the Ninety-Sixth at the time. Dismissing Durril's insistence on rectifying his previous defeat, and instead directing Durril to proceed to the Marleyvane shipyards for repairs, he instead inquired with Thrawn about the amount of time he would require to execute his initially proposed reconnaissance and intelligence gathering. Thrawn responded that he had already completed it and could proceed with the operation to retake Scrim whenever Donassius desired. Satisfied, Donassius instructed Thrawn to proceed at the Chiss Admiral's convenience.
The character of Jok Donassius made his debut in Timothy Zahn's 2017 novel titled Thrawn. He was later visually depicted for the first time in the fourth installment of the comic adaptation of the novel, specifically Thrawn 4. Within this comic issue, there are multiple instances where Donassius's dialogue is erroneously attributed to Admiral Durril in several panels.