Heretic Sangheili Major

Background
Heretic Elite Majors are denoted by their golden armor. They serve as commanders to the Minors and the Heretic Grunts. They also guard places as designated by the Heretics leader, Sesa 'Refumee. It's very likely that the Majors remained inside of the facility they used as a base, patrolling the long and dark hallways of the Threshold Gas Mine on foot, while numerous Minors patrolled the outside by way of Heretic Banshee, making the mine almost solid in defense. They are fearless warriors that ensured that their jobs are done well. They were enemies in the level The Arbiter, but they were also present in The Oracle. Most, if not all, were killed when the gas mine fell into the depths of Threshold, after the Arbiter cut the cables holding the mine above Threshold.

However, the Prophets sent in squads of Special Operations Elites and Grunts, accompanied by the Arbiter, to quell the heresy and the group infiltrated the mine and completed their objective. It can be assumed that all of the Heretics Majors were killed either by the infiltration group, by the Flood they released into the facility, or when the cables holding the station were cut by the Arbiter, sending the structure into the depths of Threshold.

Trivia

 * They are one of the least used Bipeds in the Halo trilogy, as they only appear on two levels; the Arbiter and the Oracle in Halo 2.