Sentinel emitter

This article is based on canon information, but the article's title is conjectural and/or uses descriptions as the title, as there is currently no official name for the subject.

An Aggressor Sentinel emerging from a Sentinel emitter.

Sentinel emitters are small armor-covered devices built into the walls of Forerunner facilities. Aggressor Sentinels are sometimes deployed via these devices when reacting to a Flood outbreak or other situation. They can be found in numerous locations, such as the sentinel wall, the control room, Installation 00's cartographer, and the Absolute Record.

Overview

When hostile entities, such as the Flood, are detected in the immediate area, the sentinel emitters open their covers and dispense Aggressor Sentinels. When releasing an Aggressor, the emitter emits a noise that increases in pitch until the Aggressor appears.

A sentinel emitter is at its most vulnerable when its armored cover opens to release an Aggressor. It is the most susceptible to overcharged plasma pistol shots, plasma explosions, and even physical attacks. Upon destruction, a sentinel emitter emits an electromagnetic pulse to its surroundings.

A sentinel emitter, however, is linked to Sentinel Defense Network on Installation 00. When Voridus disabled the Defense Network, the Sentinels cannot launch from it, resulting in the Flood are able to clog many of emitters due to the network is inoperable. When the Defense Network is reactivated, the Sentinels are once again can be launched to resume their duty.

Gameplay

In Halo 2, sentinel emitters can only be found in the campaign level Sacred Icon, and consistently release Aggressors to combat Flood combat forms and Thel 'Vadam.

In Halo 3, sentinel emitters can be found in the campaign levels The Ark and Halo. In addition to being allied with John-117, they are also more durable and release Aggressors at a quicker rate than those in Halo 2. In addition, the hatch closes immediately after the Aggressor is released to prevent weapon fire from getting into the emitter, although this can be bypassed by throwing a grenade before it closes.

In Halo Wars 2: Awakening The Nightmare, Protector Sentinels and Aggressor Sentinels mainly appear from a variant of Sentinel emitter called Launching bays. They can only be disabled temporarily by Voridus' EMP fields and when operating, they come in an endless wave.

In Halo Infinite, sentinel emitters cannot be destroyed, but are more akin to entry corridors and will not generate extra Sentinels beyond the ones that are scripted to appear normally. Emitters can deploy Aggressors, Eliminators and Regulators. Sentinel emitters can be found in the campaign missions Nexus, The Command Spire, Repository and Silent Auditorium.

Trivia

• With the Rocket Launcher you can lock onto Sentinel emitters as if they were vehicles. In fact the Halo 2 Editing Kit reveals that's exactly what they are, and work by having sentinels exit the emitter as if they were exiting a vehicle.
• In Sacred Icon, there are many destroyed Sentinel emitters found throughout the level. Despite appearing destroyed, these emitters can be destroyed again (with the armored cover falling out). This is easily seen in the gondola room where, after pressing the holo-panel, all the Sentinel emitters are destroyed, including the ones that are already destroyed.

Gallery

Halo 2

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  An inactive sentinel emitter at the sentinel wall.

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  A destroyed sentinel emitter at the sentinel wall.

Halo 3

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  A sentinel emitter moments before deploying an Aggressor.

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  A destroyed sentinel emitter on Installation 00.

Halo Infinite

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  Concept art of a sentinel emitter (right).

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  Render of the sentinel emitter.

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  Render of the sentinel emitter.

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  A sentinel emitter without its cover.

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  A sentinel emitter in a Reformation Spire.

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  A sentinel emitter deploying an Aggressor.

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  Four sentinel emitters in the Nexus.

List of appearances

• Halo 2 (First appearance)
• Halo 3
• Halo 2: Anniversary
• Halo: Escalation
• Halo Infinite