Mark Temple

"Fate is not without irony. And the past is not without its just dessert."

- Temple revealing his true intentions

Temple is the leader of the Blues and Reds, a faction of Simulation Troopers much like the Reds and Blues. He is the main antagonist of Season 15.

Past
Not much is known about Temple's past, except that he has served as leader of the Blues and Reds since the dawn of Project Freelancer. It's implied he may have some form of personal connection with Washington and Carolina of Project Freelancer that goes beyond the vengeful grudge he bears towards the project as a whole.

Attack on UNSC
After the events of the Chorus Trilogy which led to the arrest of Malcolm Hargrove, the Blues and Reds began carrying out their terrorist attacks on the UNSC, specifically the Project Freelancer personnel, leading the galaxy to believe the Reds and Blues were responsible for the attacks in the name of the planet Chorus. Temple lands at a UNSC outpost after the rest of his troopers kill nearly everybody. One lone survivor goes to attack Temple, but Surge kills him before he lands a strike, leaving Temple's helmet half-covered in the soldier's blood. He leaves his helmet behind before they leave.

Meeting the Reds and Blues
The Reds and Blues, having tracked a message from Church across several different locations, finally meet the Blues and Reds at their own outpost, which appears very similar to Blood Gulch. Temple introduces himself and his men, and tells the Reds and Blues about their attacks. He claims they are defending themselves against the UNSC, and further claims someone high up in their food chain is wiping out any trace of Project Freelancer, including the Simulation Troopers. As if to illustrate his point, UNSC aircraft fly near the base and begin an attack. The Reds and Blues and Blues and Reds work together to take down their attackers, taking cover in their base, which is actually underwater. After a recon mission together goes swimmingly, Temple begins to sow seeds of doubt into the Reds and Blues, turning them against Dylan Andrews, a reporter from the Interstellar Daily who is writing the true story about the Reds and Blues and defends their innocence.

True Colors Revealed
Washington and Carolina, during their own search, deliberately activate their tracking beacons to trap their mystery attackers. Surprised to find both teams of Simulation Troopers arrive, they are taken back to the Blues and Reds base and are updated on the situation. Temple gives Washington and Carolina a "tour" of the base, showing them a room filled with replicas of Freelancer armor. However, Washington and Carolina realize these are not replicas, but the actual bodies of Freelancers, having been armor-locked and left to die in the room. Temple boldly admits his true intentions to the two Freelancers after armor-locking them into the room as well. Temple mockingly challenges them to survive longer than the other Freelancers who died in there (8 days and 11 hours, to be exact) before stating the Reds and Blues will be dead before they even know what is going on.

Trivia

 * Temple is the third most depraved villain of the series with Malcolm Hargrove as the first and Felix being the second.
 * Incidentally, all three were originally presented as benevolent individuals before their true colors were revealed.