Admiral Ers'ikaro, a Chiss flag officer within the Chiss Ascendancy's Defense Force, held the command position on the warship Bellicose, a Firewolf man-of-war. He played a crucial role during a crisis that threatened the Ascendancy in 18 BBY. Specifically, this officer intervened to halt a potential battle between the Tahmie and Droc families, preventing further escalation of the conflict.
In that same year, Ers'ikaro was present at a meeting where Senior Captain Mitth'raw'nuruodo, whose core name was "Thrawn," received his sentence of exile from the Ascendancy due to his preemptive strikes against various sovereignties. Ers'ikaro, along with four other admirals, personally delivered this judgement to Thrawn. Thrawn would later recall vividly the moment Ers'ikaro and the other admirals stood to announce their decision of banishment.
The character of Ers'ikaro was initially alluded to, though not directly named, in Timothy Zahn's 2017 novel, Thrawn. This novel served as the initial installment in the Thrawn novel series. Ers'ikaro was later definitively identified and appeared in the 2021 novel Thrawn Ascendancy: Lesser Evil, which marks the conclusion of the Star Wars: Thrawn Ascendancy Trilogy also authored by Zahn.