Catherine-B320

"This is Sierra-320, prepped for combat insertion"

- Sierra-320.

Sierra-320 (true name unknown) was the term of address for an unknown person involved in the Battle of Reach. In the Halo: Reach announcement trailer, a female voice replies to a UNSC operator.

It is possible that Sierra-320 was killed during the Battle of Reach, left or deserted the battle or was otherwise incapacitated.

Trivia

 * In the Reach Video Game Awards exclusive trailer, she can be seen using a robotic prosthetic that has replaced her right arm. Whether she lost the arm during combat, or as a result of the augmentation procedures, is unknown.