Far Sight Lost was a Covenant Destroyer, part of the Combined Fleet of Righteous Purpose. In 2552, it was sent on the mission to Onyx with the Incorruptible's battle group. It was commanded by a veteran Elite Ship Master named Qunu.
When they arrived at the Human-colonized Onyx, the Far Sight Lost was sent ahead of the fleet as a communication spearhead and tried to make contact with the Onyx Sentinels in orbit around the planet, using a channel once used by the Forerunners. The Sentinels responded in brevity by destroying the Far Sight Lost with ease.