Battle of the Quarantine Zone

Background info
One of the few four-sided battles of the 9th Age of Reclamation, the Covenant and UNSC fought through the Quarantine Zone, through massive numbers of Flood Combat Forms and Infection Forms to reach the Index, required to activate Delta Halo - the Covenant to use it, the humans to stop its use. Meanwhile, the Delta Halo Sentinels, Sentinel Majors and Enforcers attempted to stop the escape of the Parasite, and repel the invading Covenant and UNSC forces.

The Arbiter was deployed by the Prophets to lower the Library's shields, assumed to be a suicide mission - instead, he succeeded and, with the help of Rtas 'Vadumee, reached the Index, subduing Commander Miranda Keyes and Sergeant Major Avery Johnson, and claiming the index, only after fighting through legions of Flood - and was presumed killed by the Brute Chieftain Tartarus, when he was blasted over the edge of the platform which surrounded the Index.