Key mind

The Key Mind is an advanced form of Flood Gravemind.

Description
Key Minds are formed by the complete assimilation of planetary ecosystems by the Flood. They are larger and hold more intelligence than a regular Gravemind. They are capable of extraordinary strategic planning, such as controlling entire battle fleets, and more than a match for metarch-class ancillas.

List of appearances

 * Halo: Silentium