- “Damn silly name.”
The Guardian of the Luminous Key was a member of the Covenant whose arrival in the Ascendant Justice was awaited by the Covenant forces stationed at Alpha Halo. He was briefly mentioned in a Covenant message translated by Cortana. Interestingly this specific being was never mentioned, although with a title as dignified as this, it is likely that the being in question is a Prophet.
It is most likely that this being was the Minor Prophet in command of the Ascendant Justice during the events of Halo: The Flood. Upon failing to make contact with High Charity, this Prophet took tactical control of the Covenant fleet at Alpha Halo, making decisions against the wishes of Thel 'Vadamee. After the Prophet had spread the available Covenant forces too thin (by sending a detachment lead by Sesa 'Refumee to investigate the Threshold gas mine) and ordered the execution of Soha 'Rolamee, Thel discovered that the prophet was responsible for releasing the Flood from the containment facility and the subsequent infection of the Infinite Succor. Thel disembarked from the Seeker of Truth to detain the Prophet, but the Prophet fled to the Truth and Reconciliation. There, Major Silva's forces captured the Prophet as they raided the ship to leave Alpha Halo. The Prophet died when First Lieutenant McKay destroyed the ship's engine power plant in response to the Flood's presence, causing the ship to crash to the surface of Alpha Halo.
- It is possible that this individual's name is related to the Forerunner Crystal, a mysterious Forerunner artifact pursued by the Covenant during the events of First Strike.
- It is also possible that his name was related to the Activation Index, although there is no other evidence that the Covenant knew of it before the events of Halo 2.