From Halopedia, the Halo wiki

The Citadel in 2552, a major Clarion facility that was the focus of the final battle of the Human-Covenant War.

Clarions are a network of facilities constructed by the Forerunners on the Ark, consisting of a superluminal communications array capable of relaying instructions to the Halo Array.[1] One such facility, known under the name of the Citadel, was the site of the final battle of the Human-Covenant War and the site at which the Ur-Didact fired the array at the end of the Forerunner-Flood war.[2][3]


Clarion facilities host the interfaces for the supraluminal communications network that allow the Ark to send commands to the Halos, such as ordering them to fire.

Known clarions[edit]

List of appearances[edit]


  1. ^ a b Halo: Divine Wind, chapter 8
  2. ^ a b Halo 3, campaign level The Covenant
  3. ^ Halo Mythos, chapter Activation of the Array, page 34-35