Mendicant Bias

Mendicant Bias is a contender-class Forerunner AI, created to defeat a Compound Mind. However, he became rampant, and sided with the Flood. He attempted to reach the Ark to halt the Array sequence, but was stopped by Offensive Bias.

He apparently still exists on the Ark and/or the new created Halo ring, as an unknown entity sends the player messages in each Terminal upon taking over the system, and this entity eventually even clearly tells the player, "I am Mendicant Bias."