Anna C. River

"'We don't get to mourn today, but Thermal won't be forgetting the sacrifices Spartan River committed in order to give Humanity a valuable victory today.' -Spartan Chandler regarding the death of Spartan River on Requiem"

Background
As a member of Fireteam Thermal, Spartan River had previous special forces and stealth operations training and operational history which made her a prime candidate for Thermal's mission criteria. Anna River was a former ODST demolitions expert and conducted many missions alongside O.N.I. operatives in operations of sabotage, asset denial, and recon against the Covenant during the war.

Her familiarity with the critical missions carried out during her ODST career made her stand out and receive recommendation from an O.N.I. officer whom she had saved during their campaigns together. The O.N.I. officer noted in his recommendation that River was already collected and mission oriented, ready, and often times seemingly eager to make the ultimate sacrifice for the sake of slowing down the Covenants advances. This acknowledgement would ring true four years after joining Fireteam Thermal.

Requiem Campaign
After being prematurely deployed along with the rest of Fireteam Thermal when the Infinty first arrived and crash landed on Requiem Spartan River with the rest of Thermal were forced into various Forerunner structures and portals fleeing Promethean forces. Eventually being intercepted by friendly Sentinel forces who lead Thermal to Command Site Citadel. Here Spartan River and Thermal would hunker down for eight months when Captain Del Rio refused to exfil the Spartan team who had apparently gone AWOL.

When the Infinity did return Thermal was immediately resupplied and Citadel was converted into a ground command center for UNSC forces. Thermal's leader, Spartan Chandler, would lead all Spartan forces in the immediate area under orders of Spartan Commander Palmer in what would become known as Thermal Ops. During Thermal Ops, Spartan River was a critical member of an operation to restrict Promethean forces from the region through the detonation of a Forerunner Portal Hub.

Operation Big Hit, Objective 'Plan B."
During the operation Covenant and Promethean Forces overwhelmed the UNSC force and were able to shut down the explosive device timer. The UNSC Forces by now were on the retreat expecting the detonation to neutralize the enemy force and deem the operation a strategic victory. Spartan River, aware of the timer being shut down sacrificed herself to return to the bowels of the forerunner site and manually detonate the explosive which would claim her in the blaze.

Trivia

 * Spartan River was the only casualty experienced by Thermal during its operational history up to 2558.
 * The loss of Spartan River deeply effected Fireteam Thermal's leader, Spartan Chandler, who had also lost his entire ODST team during the Battle of Cascade in 2552.