Rookie

The Unnamed Marine is a UNSC Marine Shock Trooper, and served in Mombasa, Kenya in 2552. He is the only apparent survivor of his unit after the Prophet of Regret's slipspace jump devastated the city and the mid-air ODST's.

It is suggested, in some of the lead up information to the release of the full trailer for Halo 3: Recon that he may be a SPARTAN-I, with the rank of Captain. This would explain how he survived a drop and crash with a 99.99% expected fatality rate (later corrected to 00.52%), with only battered armor and a 8 hour period of being unconscious to show for it.

This likely incorrect, at the time of impact, the Superintendent displayed the message "Motor Vehicle Crash!" and when searching for the debris though the smoke, the SI displayed "Acquiring Vehicle ID..." which means it is more likely that the AI believed the HEV to be one of the normal cars or trucks inside the city crashing, and estimated accordingly.

Trivia

 * He is the main character of Halo 3: Recon, a prologue and expansion pack to Halo 3, due out in Fall 2009.
 * His main weapon is a modified M7S Caseless Submachine Gun with laser sights.