O'Brien (Another Day at the Beach)

"Sir, O'Brian's down"

- Private Walpole .

O'Brian was a UNSC Marine and Orbital Drop Shock Trooper stationed at Earth in 2552. He was probably part of the 7th Orbital Drop Shock Trooper Division.

During The First Battle of Earth, his squad was dispatched from the UNSC In Amber Clad to relieve the ground forces. Their Pelican was shot down over Old Mombasa by a Scarab walker, O'Brian was killed in the crash. It is unknown what other engagements he was involved with.

Trivia

 * O'Brian is named after the Bungie employee Bill O'Brien, who worked on the animations and cinematic for Halo 2.