Steward Sentinel

"Stewards: These Sentinels accompany other Forerunner machines and assist them with their tasks, using a combination of support systems and offensive weaponry.The largest constructs are classified as strato-sentinels, taking the roles of grand builders and overseeing architects for major Forerunner works. Those used in military applications were often classified as weapon-ships, capable of being fitted with naval-scale ordnance and defensive systems."

- Jeff Easterling

The Steward is a variant of Strato-Sentinels, Strato-Sentinels are designed to perform terraforming projects, and are capable of mining moons, asteroids, or other planetary bodies.

Description
Dark gray in color, Strato-Sentinels are massive and powerful Sentinels that are slightly smaller than the average human frigate, which are about 478 meters in length. The upper section of a Strato-Sentinels is vast and wide, while the lower section is lined with numerous mechanical, tentacle-like "legs" that move in pursuit of objects. Glowing eye-like lights are installed on the front of each Sentinel.

Roles
Strato-Sentinels were used by the Forerunners as escorts to keyships and larger Sentinel variants.

The Forerunners utilized Strato-Sentinels to help in the construction of the Halo rings, such as the newly constructed Installation 08 in 2552.

Prehistory
Strato-Sentinels were used as escorts during the Forerunner-Flood war. Following the firing of the Halo Array, Strato-Sentinelsassisted the keyships with the reintroduction of species throughout the Milky Way, as per the Conservation Measure, accompanying the vessels back to species' homeworlds. Strato-Sentinels assisted with the excavation and construction of a massive slipspace portal on Erde-Tyrene, in the present-day country of Kenya, that had been set into motion by the Librarian before her death. These Strato-Sentinels were spotted by the human tribe elder N'chala, in the years after the reintroduction, who mistook the sentinels for gods.

Behind the scenes
Strato-Sentinels were originally planned to appear in Halo 3, but were ultimately cut from the game. One of the early settings for the maps "Construct" and "Blackout" was the interior of a damaged Strato-Sentinels in orbit around the Foundry, where other Strato-Sentinels could be seen in the distance harvesting materials from the Foundry's resource moon. However, this idea was scrapped. During production, they were known as "Strato-Sentinels", a name that would later be adopted in subsequent canon. The Strato-Sentinels were also intended to be included in Halo 4, though they were removed from the game during the pre-production stages.

List of appearances

 * Iris
 * Halo 3: The Cradle of Life
 * Halo Legends
 * Origins
 * Halo Mythos
 * Halo: Renegades
 * Halo: Outpost Discovery