It was a veteran vessel, having seen numerous engagements, including the Battle of Sigma Octanus IV, where it took a Plasma Torpedo to its bow starting fires in its foredecks. After the Battle at Sigma Octanus, Leviathan returned to Reach. It was destroyed during the Fall of Reach, with Admiral Stanforth among the crew that perished in the battle.
- The ship may have been named after the Leviathan, a gigantic sea beast of Hebrew legend.
- Halo: The Fall of Reach (First appearance)