After the ship was heavily damaged, the crew was forced to abandon ship in lifepods. Half of the pods that were jettisoned were exposed to a radiation pulse from the ship's engine, exposing the remaining crew to large amounts of radiation, causing most of them to die painful deaths aboard the UNSC Spirit of Fire. This same radiation was reported to have affected the AI, as Serina reports that it "may act peculiar." When Sergeant Forge was sent to the Prophecy to recover survivors, he was redirected by Serina to purge the NAV database of the ship. He was initially prevented from doing so by FitzGibbon due to his "unprofessional record," but after Forge told him he was breaking the Cole Protocol, FitzGibbon allowed him to do the purging. After the task was finished, FitzGibbon self-destructed the UNSC ship in order for the ship not to be captured by the Covenant. He destroyed himself in the process.
Like the later AI Wellsley, FitzGibbon took the form of an 18th-century officer in the British Army.
- FitzGibbon is likely named after James FitzGibbon, British officer and hero of the War of 1812. FitzGibbon is known for his participation in the battles of Stoney Creek, Beaver Dams, and Lundy's Lane. Despite being British, he is often considered a Canadian hero.
- Halo Wars: Genesis (First appearance)