Retriever Sentinel

The Retriever is a Forerunner Sentinel variant. Retrievers are designed to perform terraforming projects and capable of mining moons, asteroids, or other planetary bodies, such as the resource moon located in the middle of Installation 00. They were also used to help in the construction of the Halo rings, such as the newly constructed Installation 04. They were also used during the construction of the Portal on Erde-Tyrene, in the present-day country of Kenya.

Trivia
Sentinel Retrievers were originally planned to appear in Halo 3, but were cut from the game. During production, they were known as "Strato-Sentinels".

List of appearances

 * Halo 3: The Cradle of Life
 * Halo Legends
 * Origins