Protector Sentinel (Trove)

Protector Sentinels are a specialized variety of Forerunner Sentinel.

Overview
In Halo Wars, Protector Sentinels are smaller, faster, and occupy less of the population limit than standard Aggressor Sentinels. It is in the support role that they excel - their Y-button ability is to attach themselves to one of the player's other units, following it in action. Only one can be attached to a single unit one time.

For the most part, they must be purchased from a Protector Plant.

Variations
There are three different variants of the Protector Sentinels:
 * Offensive Protector - when attached, it attacks units near its host with a pulse of laser fire.
 * Shield Protector - projects a rechargeable energy shield around its host unit.
 * Healing Protector - recharges its host's health when out of combat.

Offensive Protector
The Offensive Protectors are the only Protectors that can be used as a standard unit, because they can attack without being assigned to a squad. In direct combat, they are less effective than standard Aggressor Sentinels. However, similar to the Sentinel Majors, they are equipped with an onboard beam weapon which fires a single blue colored beam. They are of similar shape to the Watcher Sentinel, but are slightly bigger than a Constructor. They have a laser targeting system that constantly scans the nearby area for threats. Offensive Protectors are the only available variant in the Campaign of Halo Wars.

Healing and Shield Protector
The Healing and Shield Protectors are the about the same size as Offensive Protectors - smaller than a standard Aggressor but larger than a Constructor. Unlike the Offensive Protectors, both variants do not possess guiding lasers. The Healing Protectors and the Shield Protectors are identical in shape; Healing Protectors differs from Shield Protectors as they radiate a green aura. Shield Protectors have the ability to form a protective shield around its host, similar to the bubble shield, whereas Healing Protectors have the same ability as an UNSC Marine with the Medic Upgrade, meaning they heal the squad after combat.

Spartan and Regret Uses
Unlike most units which are limited to only one Protector Sentinel, Spartans and the Prophet of Regret are able to receive multiple Protector Sentinels assigned to them due to their "special units" feature.


 * Prophet of Regret: Upgrading the Prophet of Regret with Ancestral Perversion will give him two Offensive Protectors for his personal protection.


 * Spartans: There are two methods of getting two Protectors assigned to a Spartan where the Spartan has to hijack a vehicle:
 * The Spartan and one of your vehicles must acquire a Protector assigned to them. Order your Spartan to commandeer your vehicle. This only works when it is your vehicle as when you hijack an enemy vehicle, the vehicle's Protector will be destroyed in the hijacking process.
 * The Spartan must have an assigned Protector. The Spartan then hijacks an enemy vehicle or commandeer a friendly vehicle. After commandeering a vehicle, assign another Protector to the vehicle. If that vehicle is destroyed, the Spartan would still eject as normal, but will only keep the Protector that was assigned to them before commandeering a vehicle.

Wraith and Locust Uses
Wraiths and Locusts have the opportunity of multiple shields because they have shields and assigning a Shield Protector would give them a second one.


 * Wraiths: They require the Heavy Shield upgrade for this trick to work.


 * Locusts: They have shields by default, you don't need an upgrade. It's very helpful for the Locust because they can still have a shield when they use the Overdrive ability.

Trivia

 * Players can purchase them inside the Protector Plant found on the map Labyrinth.
 * If an unit is being airlifted by the Transport power, the Protector unit will follow the Pelican, providing it with its capabilities. When the Pelican reaches its destination, the Protector would be reassigned to its original host.
 * Offensive Protectors are the only variant that appear in the Campaign. Ensemble Studios may have had ideas to add the other variants but due to balance issues, these were only available the multiplayer segment. The other ones would have been set to protect other Sentinels, but it would affect the gameplay and render them harmless. Furthermore, the Offensive Protectors that appear in the Campaign never attach to other Sentinels.
 * The shield that the Shield Protectors give to assigned units protect them from being 'stunned' as well.
 * If you attach one of the other two Protectors to the Prophet of Regret before researching Ancestral Perversion, one of the Offensive Protectors will not appear when you do research it.