Sentinel

Sentinels are Forerunner machines designed for the construction; maintenance and protection of their machines. Due to the broad range of duties, there is also a broad-range of sentinel variants.

Aggressors
Sentinel Aggressors are designed for the protection of Forerunner machines and the eradication of Flood forms. There are many forms of Aggressor, though most follow the same basic layout: a floating weapons-system. Bog-standard Aggressors consist of the "sentinel beam", combined with some form of anti-gravity technology to enable flight.

Constructors
Constructors are smaller forms of sentinel designed for the construction and servicing of Forerunner structures. It was these sentinels that built the quarantine zone on Installation 05.