From Halopedia, the Halo wiki
He was the commanding officer of the Remote Scanning Outpost Fermion in 2552. Chief McRobb was reassigned to the station from Fort York on the edge of the Inner Colonies after the battle of Sigma Octanus IV. He was a brilliant mathematician, and was given command of the station due to his leadership and mental talents.
In August 2552, three months after his reassignment, Chief Petty Officer McRobb detected a fleet of some 300 Covenant ships inbound to Reach. His quick action alerted FLEETCOM in time to muster a defense for the planet. Unfortunately, McRobb was killed when he ordered the destruction of the Fermion as per the Cole Protocol.
McRobb was highly disciplined and ran a tight operation, making sure his men kept their stations spotlessly clean. He was strict and by-the-book. He was also extremely vigilant of his post, thinking that becoming too laid-back would get Reach attacked, a possibility he compared to Pearl Harbor.
List of appearances