From Destinypedia, the Destiny wiki
Standard Bearers are a powerful Elite class of Loyalist Cabal Centurions that appeared in the Leviathan Raid. Nightmare versions are also encountered during the Duality Dungeon, along with a new Psion variant.
Standard Bearers guard the keys that Guardians need to unlock the doors that lead to different sections of the raid. They must be quickly disposed of to gain access to the door.
List of appearances