Petty Officer Second Class Mica-311 (full name Mica Bernadette Helena at birth, also known by the designations Sierra-Three-One-One and Codename: CRIMSON TWO) was a highly experienced special forces operator and junior officer of the UNSC Navy during the last days of the Human-Covenant War as a SPARTAN-II Commando of Project ARES, the third class of the SPARTAN-II Program, serving in the Special Operations Detachment Crimson Team. Taking part of several notable battles during the war, including the Siege of Paris IV, the Battle of Sigma Octanus IV, the Fall of Reach, the Battle of Tribute, the Battle of Earth, and the Battle of Dosiac, she proved herself an extremely capable soldier and commando before meeting her end on Doisac.