Editing Sentinel

{{Status|Canon}}
{{Center|This is about the Forerunner constructs. For the UNSC AI type, see [[Navy Sentinel]]. For the achievement, see [[Sentinels (achievement)]].}}
[[File:H2-EnforcerSentinel-ScanScreen.jpg|300px|thumb|An [[Enforcer]] flanked by two [[Aggressor Sentinel|Aggressors]].]]
'''Sentinels''' are machine-servants{{Ref/Book|[[Halo: Warfleet – An Illustrated Guide to the Spacecraft of Halo]]|Section=Glossary|Page=92-93}} created by the [[Forerunner]]s, designed for the construction, maintenance and defense of their structures and facilities.<ref name="p167">'''[[Halo: The Essential Visual Guide]]''', ''page 167''</ref> Various Sentinel variants exist, each tailored to a specific task; because of its ubiquity, the [[Aggressor Sentinel|Aggressor]] variant is often referred to simply as the "Sentinel". Most variants are produced by [[Sentinel manufacturing facility|Sentinel manufacturing facilities]], [[Sentinel factory|Sentinel factories]], or [[Sentinel launcher]]s. The Sentinels were revered by the [[Covenant]] as "holy warriors of the [[Halo Array|Sacred Rings]]",<ref>'''[[Halo 2]]''', campaign level ''[[The Arbiter]]'' - ''"A Whisper in the Storm"''</ref><ref>'''Halo: Hunters in the Dark''', ''page 83'' (Google Play edition)</ref> despite engaging them in combat on various occasions.

==Overview==
The Sentinels follow the command of the [[monitor]] or other [[ancilla]] that is in charge of the facility they are assigned to, but even without central direction, they are able to respond to threats against their assigned installations with remarkable coordination and effectiveness.<ref>'''Halo Wars 2''', ''[[Phoenix Logs]] — Forerunner Sentinels''</ref><ref>'''[[Halo Wars 2]]''', campaign level ''[[Under The Dark]]''</ref> On [[Installation 00]], a sentinel defense network is used to coordinate the Sentinels on the Ark despite [[000 Tragic Solitude|the monitor]] no longer being present. Sentinels follow their directives even if this entails engaging other Forerunner machines. For example, the Aggressor Sentinels of [[Requiem]] remained loyal to the [[Librarian#Imprint on Requiem|Librarian]] against the [[Ur-Didact|Didact]]'s [[Promethean#Mechanical Prometheans|Promethean]]s in [[2557]]. Another instance is when the Constructors of [[Genesis]] remained loyal to [[Monitor]] [[Exuberant Witness]] against the [[Created]]'s Promethean forces in [[2558]]. 

===Sentinel Defense Network===
A Sentinel Defense Network is a system that coordinates sentinel defenses to perform their duties in defense of an installation. All Installation has the Defense Network installed and each has its own protocol. Without the defense network activated, Sentinels are unable to perform their duties. This, however, does not affect the stationary defenses, which remain active even if the defense network is shut down, including [[containment shield]]s.<ref>'''[[Halo Wars 2]]''', Campaign level ''[[The Archive]]''</ref> The Defense Network itself is separated to local and global defense network. The local defense network only controls sentinels surrounding terminals, while the global defense network controls defenses on a global scale. The Defense Network is linked with every defensive protocol on the installation. [[Containment protocol]] on Installation 00 is linked with the Defense Network and Sentinels cannot conduct the protocol if the network is disabled. 

[[Installation 09]] heightened the security protocol and immediately launched a [[Retriever Sentinel]] to cleanse the humans and the Banished present on the rings as soon as it left Installation 00. Professor Anders successfully hijacked the local network through the control tower to temporarily take control of Retriever Sentinel to disable barriers around the control room.<ref>'''[[Halo Wars 2]]''', Campaign level ''[[The Halo]]''</ref>

The Smart AI Isabel manipulated the Sentinel Defense Network to her own ends by hijacking ''[[Enduring Conviction]]'' and firing its energy projector on the Ark, causing Aggressor Sentinels to swarm on the ship and bisect it.<ref>'''[[Halo Wars 2]]''', Campaign level ''[[Under the Dark]]''</ref>

When Voridus shut down the Sentinel Defense Network, all Sentinel activities are ceased immediately, giving Voridus a clear path to the High Charity without any opposition.<ref>'''[[Halo Wars 2]]''', Campaign level ''[[What Could Go Wrong?]]''</ref> When Voridus reactivate the Sentinel Defense Network, the Sentinels were immediately resumed their duty, allowing Pavium and Voridus to call in Retriever Sentinel to defeat Proto-Gravemind.<ref>'''[[Halo Wars 2]]''', Campaign level ''[[Manifestation]]''</ref>

==Types==
*'''[[Aggressor Sentinel]]''' - The Aggressor is the most common form of Sentinel, designed for the protection of Forerunner constructs and the small-scale suppression of Flood forms.{{Ref/Reuse|p167}} There are many forms of Aggressor, though most follow the same basic layout. In the event of a severe threat, an advanced version of the Aggressor would be dispatched to assist the more common Aggressors.
<gallery class="center">
File:H4 Sentinel.png|One type of Aggressor Sentinel.
File:H2A Silver sent.png|A different type of Aggressor Sentinel.
File:H2A Gold Sentinel.png|A [[Aggressor Sentinel Eliminator|gold Aggressor Sentinel]].
File:HINF SniperSentinelCrop.png|A [[Sniper Sentinel|Sniper Aggressor Sentinel]].
</gallery>
*'''[[Assembler Sentinel]]''' - Assemblers are presumably used to build and maintain Forerunner installations and technology, like the similarly named Constructors. Though they are not designed for combat, they will suspend their primary duties and engage Flood forms in the event of an outbreak.{{Ref/Reuse|p167}}
*'''[[Constructor]]''' - The Constructors are specialized Sentinels, designed solely for the construction and servicing of Forerunner structures. Like Assemblers, they are not designed for combat, but they will engage the Flood if necessary.{{Ref/Reuse|p167}}
<gallery class=center>
File:H3-SentinelConstructor.png|One type of Constructor Sentinel.
File:H5G-Constructor.png|A different type of Constructor Sentinel.
</gallery>
*'''[[Controller]]''' - These sentinels were typically used to defend valuable technology on Installation 00. Their typical weaponry is a supercharged [[sentinel pulse]] as their main weapon, with a [[Sentinel beam]] to cover their blind spot. For defensive purposes, they can create an energy shield on their forward side. This shield is significantly stronger than that of the [[Enforcer]].<ref>'''Halo Wars 2'''</ref>
<gallery class=center>
File:HW2-Controller.png|A Controller Sentinel.
</gallery>
*'''[[Council sentinel|Council]]''' - A special variant of Sentinel was used aboard the Forerunner [[Capital]] for security purposes. They possessed black armor, matching the black-and-red armor of [[Ecumene Council]] security personnel.<ref>'''Halo: Cryptum''', ''page 294''</ref>
*'''[[Enforcer]]''' - The Enforcers are equipped with a variety of offensive and defensive measures, including [[pulse beam]]s, [[Forerunner missile launcher|missiles]], a last-resort [[Sentinel beam]], and three frontal [[energy shielding|energy shield]]s.{{Ref/Reuse|p167}} They are designed to handle major Flood outbreaks, but are also capable of defending their Installation from other external threats.
<gallery class=center>
File:Enforcer.png|An [[Enforcer]] Sentinel.
</gallery>
*'''[[Gatherer]]''' - Gatherers seem to be deployed exclusively on [[Line installation]]s, and serve as collectors of biological specimens for the resident [[Monitor]]. They have offensive capabilities similar to Aggressors.<ref>'''Halo: Blood Line'''</ref>
<gallery class=center>
File:HBL-Issue1-FullPage-TheGatherer.jpg|A Gatherer Sentinel.
</gallery>
*'''[[Guardian Sentinel]]''' - A large type of Sentinel.{{Ref/Map|Halo 3|[[Epitaph]]}}
<gallery class=center>
File:H3 Epitaph Hologram.png|A [[hologram]] of a [[Guardian Sentinel]].
</gallery>
*'''[[Monitor]]''' - A general purpose Sentinel, containing a high-level ancilla.{{Ref/Book|Id=warfleetglossary|[[Halo: Warfleet – An Illustrated Guide to the Spacecraft of Halo]]|Section=Glossary|Page=90-91}}
<gallery class=center>
File:H2A - Guilty Spark close-up.jpg|The Monitor [[343 Guilty Spark]].
</gallery>
*'''[[Promethean Watcher]]''' - The Watcher is a Sentinel variant used by [[Promethean Knight]]s for combat support. They can heal and augment their damaged allies and return incoming ordnance such as grenades using a gravity-displacement beam.<ref>[http://halo.xbox.com/halo4#!an-epic-universe/characters/8c164b48-05e7-4c13-a268-f60ec3a72938 '''Halo 4 Official Site''': ''CHARACTERS'']</ref>
<gallery class=center>
File:H5G guide - Watcher.png|A Promethean Watcher.
</gallery>
*'''[[Protector Sentinel|Protector]]''' - A type of Sentinel encompassing a few different models.
<gallery class=center>
File:HW-Protector Sentinels.jpg|[[Etran Harborage]] [[Protector Sentinel (Shield World 0459)|Protector Sentinel]]s. Roughly similar in appearance to regular Aggressors, these Protectors are modular units that can become one of three variants: Offensive, Shield, and Healing.
File:HW2 Blitz Protector Sentinel.png|An [[Installation 00]] [[Protector Sentinel (Installation 00)|Protector Sentinel]].
</gallery>
*'''[[Strato-Sentinel]]''' - A class of large Sentinels.
<gallery class=center>
File:HW2 Retriever.png|A [[Retriever Sentinel]].
File:HOD Steward Render.png|A [[Steward Sentinel]], a variant of Strato-Sentinels,<ref name="steward">[https://www.halowaypoint.com/en-us/news/outpost-discoveries Canon Fodder: Outpost Discoveries] "'''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."</ref> are massive [[terraforming]] machines, used to gather raw materials for large-scale Forerunner [[astroengineering]] projects such as the [[Halo Array]].{{Ref/Reuse|p167}}
</gallery>
*'''[[Onyx Sentinel]]''' - Onyx Sentinels both guard and make up the artificial planet of [[Onyx]]. They use a much more powerful individual energy beam than the Aggressor, and have the ability to combine and transform themselves in order to complete a specific task. Onyx Sentinels are far more formidable opponents than more widely-used "standard" variants.
*'''[[Safeguard Sentinel]]''' - Fitted with powerful sterilization beams, the Safeguard Sentinels are highly efficient at containing and cauterizing intrusions into their assigned protectorate.<ref>[https://www.halowaypoint.com/en-us/news/bounty-hunters '''Halo Waypoint''' - ''Canon Fodder: Bounty Hunters'']</ref>
*'''[[Super Sentinel]]''' - Considerably larger than Aggressors, Super Sentinels fill the same role as the [[Enforcer]]s - combating large-scale Flood outbreaks.
<gallery class=center>
File:HW-SuperSentinel.png|A Super Sentinel.
</gallery>
*'''Unidentified sentinel variants'''
<gallery class=center>
File:Origins-Unnamed-Sentinel.png|[[Unidentified Sentinel variant|A large variant]] in one of it's two forms.
</gallery>

==Production notes==
Sentinels were seen in ''[[Halo Infinite]]''{{'}}s [[Halo Infinite announcement trailer|announcement trailer]] at [[Wikipedia:Electronic Entertainment Expo 2018|E3 2018]].<ref name="HIT">''[[Halo Infinite]]'' [[Halo Infinite announcement trailer|reveal trailer]]</ref><ref name="TMOTHIAT">[https://www.youtube.com/watch?v=PTreFoLAufw '''YouTube''' - ''The Making of the Halo Infinite Announce Trailer'']</ref>

==Gallery==
===Concept art===
<gallery>
File:HW2 Concept ScourerSentinel.jpg|Concept art of a "Scourer" Sentinel for ''[[Halo Wars 2]]''.
File:HINF DiskSentinelConcept1.jpg|Concept art of a disk-shaped Sentinel for ''[[Halo Infinite]]''.
File:HINF DiskSentinelConcept2.jpg|More concept art of the disk-shaped Sentinel.
File:HINF SentinelCarrierConcept.jpg|Concept art for ''Halo Infinite'' depicting a large Sentinel seemingly designed to carry other smaller Sentinels.
File:HINF WingedSentinelConcept2.jpg|Concept art of a large winged Sentinel for ''Halo Infinite''.
File:HINF WingedSentinelConcept3.jpg|More concept art of this Sentinel.
File:HINF WingedSentinelConcept1.jpg|More concept art of this Sentinel.
File:HINF SentinelConcept1.jpg|Concept art of a different Sentinel in ''Halo Infinite''.
File:HINF SentinelMovementConcept.jpg|Concept art exploring how Sentinels move, fire, and react to damage in ''Halo Infinite''.
File:HINF SupportSentinelConcept.jpg|Concept art of a "support" Sentinel for ''Halo Infinite''.
File:HINF SentinelSketchConcepts.jpg|Concept art of other kinds of Sentinels for ''Halo Infinite''.
File:HINF SentinelSketchConcepts2.jpg|Concept art of more kinds of Sentinels.
File:HINF SentinelWeaponConcepts1.jpg|Concept art of various weapons to be used by Sentinels in ''Halo Infinite''.
File:HINF SentinelWeaponConcepts2.jpg|More weapon concepts.
File:HINF SentinelWeaponConcepts3.jpg|More weapon concepts.
File:HINF Concept SentinelThreat1.jpg|Concept art of John-117 facing down a large Sentinel in ''Halo Infinite''.
File:HINF Concept SentinelThreat2.jpg|More concept art of John and a large Sentinel.
File:HINF Concept SentinelThreat3.jpg|More concept art of John and a large Sentinel.
File:HINF Concept SentinelThreat4.jpg|More concept art of John and a large Sentinel.
</gallery>
===Screenshots===
<gallery>
File:Origins H3 Sentinels.png|A group of Sentinels, including a Strato-Sentinels, Guardians and an unidentified variant in ''[[Halo Legends]]''.
File:HOD RingExperience Interior.jpg|Hundreds of Sentinels of varying types.
</gallery>

==List of appearances==
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*''[[Halo: Combat Evolved]]'' {{1st}}
*''[[Halo: The Flood]]''
*''[[Halo 2]]''
*''[[Halo: Ghosts of Onyx]]''
*''[[Iris]]''
**''[[Halo 3: The Cradle of Life]]''
*''[[Halo 3]]''
*''[[Halo Wars]]''
*''[[Halo Legends]]''
**''[[Origins]]''
*''[[Halo: Blood Line]]''
*''[[Halo: Cryptum]]''
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*''[[Halo: Glasslands]]'' {{Mo}}
*''[[Halo: Combat Evolved Anniversary]]''
**''[[Terminal (Halo: Combat Evolved Anniversary)|Terminals]]''
*''[[Halo: Primordium]]''
*''[[Halo 4]]''
**''[[Spartan Ops]]''
*''[[Halo: Silentium]]''
*''[[Halo: Spartan Assault]]''
*''[[Halo: Escalation]]''
*''[[Halo: Broken Circle]]''
*''[[Halo 2 Anniversary]]''
*''[[Halo: Spartan Strike]]''
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*''[[Halo: Hunters in the Dark]]''
*''[[Halo: Last Light]]''
*''[[Halo 5: Guardians]]''
*''[[Halo Mythos]]''
*''[[Halo: Fractures]]''
**''[[Promises to Keep]]''
*''[[Halo Wars 2]]''
*''[[Halo: Legacy of Onyx]]''
*''[[Halo: Official Spartan Field Manual]]''
*''[[Halo: Renegades]]'' {{Mo}}
*''[[Halo: Shadows of Reach]]''
**''[[Sacrifice]]'' {{Mo}}
*''[[Halo: Point of Light]]''
*''[[Halo Infinite]]''
*''[[Halo: The Rubicon Protocol]]''
{{col-end}}

==Sources==
{{Ref/Sources}}

{{Forerunner/Sentinel}}

[[Category:Sentinels| ]]
[[Category:Forerunner technology]]