Ascendant Justice's AI

"Sneaky little bastard."

- Cortana, of the AI

There was an unnamed Covenant 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 unsuccessful as she eventually caught it and decompiled it. The Covenant AI hated that Cortana was able to improve upon Covenant technology, believing it to be heresy, and managed to send a message over the Battlenet before it was caught, both warning of the capture of the ship and sending the calculations for a sub-atmospheric Slipspace jump.

The AI demonstrated "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. When the AI faced its death from Cortana, it screamed a fractured statement: "Do what you will-wil-willwill. I go to finally to my heaven reward paradise final-finalfinalinfinityinfinityinfini-AT NONCOPYSTATE." This perhaps indicates that it saw death as salvation from fractured life induced from repeated copying.

It is this unnamed AI's code that allowed Cortana to copy the code-breaking part of her logic into another Cortana, sent with Blue Team. They effectively used this fracture of Cortana to break into and eventually destroy The Unyielding Hierophant, a Covenant Command Platform, and its resident fleet.

Trivia
The most likely reason of this unnamed Covenant AI's disgust at Cortana's improvements upon Covenant technology, is that the technology was handed down to the Covenant by the Forerunners and that technology was considered extremely sacred by the Covenant, only allowed to be altered by the ever wise San 'Shyuum.