From Halopedia, the Halo wiki
April 26, 2526 (Circinius IV)
United Nations Space Command
Foster was an officer cadet of the United Nations Space Command. He attended Corbulo Academy of Military Science in 2526.
He was present in the mess hall when a fight broke out between Thomas Lasky and Walter Vickers. He joined the crowd observing the fight alongside Beamish and Taylor.
He was presumably killed when the Covenant destroyed Corbulo Academy.