Cailean-378, formerly known as Cailean Macchruim, was a SPARTAN-II Class II supersoldier assigned to Aureolin Team, led by Javier-152. Requisitioned by the Office of Naval Intelligence immediately after augmentations, Cailean and Aureolin were deployed on top-tier black operations, including activities such as putting down rebel groups, tracking and eliminating Covenant Special Forces teams, and even neutralizing rogue ONI cells. During the Battle of Earth, they defended ONI assets and evacuated key personnel to ONI prowlers in orbit meant to transport them to a secret location. During the evacuations, Cailean was forced to leave hundreds of civilians behind to save several dropships containing ONI personnel. This event weighed heavily on his conscience, and even after the war he felt guil