Ascendant Justice's AI

There was an unnamed Covenant AI Artificial Intelligence construct used by the Covenant which was stationed on the Covenant flagship Ascendant Justice however it never identified itself with a name. When Cortana infiltrated the Ascendant Justice the Covenant AI tried to stop her, but it was mostly unsucessful as she eventually caught it and decompiled it. The Covenant AI managed to send a message over the Battlenet before it was caught, warning of the capture of the ship and sending the calculations for a sub-atmospheric Slipspace jump.

The AI appeared to demonstrate "fractured" thinking, as though it were suffering from the errors of being copied extensively. Cortana also stated that its algorithms looked very familiar leading Cortana to the possibility that a human-made UNSC AI had been captured and copied. Later, there were several security AI's aboard the Unyielding Hierophant.

At the end of Halo 2, Cortana encounters a presence based inside the Forerunner Dreadnaught thats 'fighting back' which she initially assumes is Covenant but which some have speculated is actually Forerunner. It is unknown what it is fighting, but it is most likely Flood forms trying to get aboured.