Security Fleet

The Security Fleet was a Forerunner naval group.

When the Flood began actively attacking the Forerunner military at the Forerunner core systems, the Security Fleet, along with the Suppression Fleet and the Emergency Circumstance Fleet were ordered by Forerunner Fleet Command to defend the core systems from infection by the Flood, however they were most likely overun by the the Flood eventually and perished along with the other Forerunner fleets.