From Halopedia, the Halo wiki
The Eyes are spy drones produced by the Covenant and before them, the San'Shyuum Reformists. Pre-Covenant models of Eyes used by the San'Shyuum were roughly diamond-shaped and could fly around freely. San'Shyuum commanders could observe battles from orbit by using the Eyes. Eyes were capable of projecting a holographic image of footage they captured while doing surveillance work. A San'Shyuum could interact with the hologram and highlight certain areas. They additionally kept information on certain individuals, if it was available. A San'Shyuum could have the Eye mark hostile individuals for assassination or deploy troops, orders that could be carried out by San'Shyuum forces or Aggressor Sentinels. Eyes could relay footage from other Eyes.
The Eyes were used during the War of Beginnings. During the Skirmish of the Planet of Blue and Red in 860 BCE, Eyes were used to surveil Sangheili forces. Eyes Seven and Thirteen were used to report on enemy movements during the battle. High Lord Mken 'Scre'ah'ben consulted with Eye Seven during the battle for an update on the Sangheili military's positions. While viewing footage from the Eye, Mken observed Field Commander Ussa 'Xellus. At first, the High Lord had the Eye mark the commander for assassination, but ultimately had the order belayed. Eye Seven was destroyed when Sangheili forces ambushed the San'Shyuum commander outpost. Eyes were later used by the Covenant to monitor Janjur Qom, the San'Shyuum homeworld. The Eyes revealed the Stoics' technological status to the rest of the Covenant. One Eye was once pursued by a Stoic aircraft on the planet. Various forms of Eyes continued to be used by the Covenant throughout the millennia, most recently in the Human-Covenant War.
List of appearances