Guardian of the Luminous Key

The Guardian of the Luminous Key was a member of the Covenant whose arrival at Alpha Halo was awaited by the Covenant forces stationed there during Halo: Combat Evolved. He was briefly mentioned in a Covenant message by Cortana in Halo: First Strike. It is likely, based upon the Arbiter's rank and possible presence on the ship, that the guardian was the Arbiter. He also could have been one of the elites on Ascendant Justice that was killed by Cortana.