The Guardian was a Forerunner Sentinel located at the Ark. The Guardian Sentinel was originally set to appear in Halo 3 as a fighting enemy in a Campaign level that later became the multiplayer map Guardian. The player would have been able to rip out the Guardian's eye beam and use it as a weapon in the campaign level. In the Halo: Legends episode Origins, two Guardians escort a Keyship to The Artifact.