Ascendant Justice's AI

There was an unnamed Covenant AI Associated 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 Dreadnought. The AI inside the Dreadnought is believed to be Mendicant Bias, due to the fact that it was trapped within the Dreadnought by Truth until it landed on the Ark, allowing the AI to leave the ship and go into the Ark's systems, sending messages to the player via Terminals. It is unknown why it was trying to keep Cortana from delaying the Dreadnought. It is possible (assuming this unknown AI is Mendicant Bias) that it wanted Truth to successfully activate the Halo rings in order to destroy the Flood, to compensate betraying the Forerunners during the Forerunner-Flood War. This, however, is speculation.