Pirate Trooper

Pirate Troopers are a common variety of Space Pirate in the Prime Series.

In Prime
The simple Trooper from Metroid Prime is simply known as a Space Pirate, although their Logbook scan indicates that they are the basic troopers. They are trained very well in weapon and melee combat. They are very intelligent and spend most of their time in battle, hindering Galactic Federation forces. While they are found throughout Tallon IV, most of them abide in Glacier One of Phendrana Drifts and the Phazon Mines. Different variants of the Prime pirates exist, such as Shadow Pirates and Flying Pirates. A special group of Pirate Troopers known as Trooper Pirates appear and are only vulnerable to the same Beam technology from which their their armorsuits are derived. They are only found in the Phazon Mines. Pirate Troopers are sometimes used as bait for Metroids in their Quarantines.

In Echoes
During the events of Metroid Prime 2: Echoes, Pirate Troopers' arsenals include a photonic power scythe and quantum assault cannon, which at the time were standard-issue weapons for their rank. Most troopers were stationed at their base in Agon Wastes, which was constantly targeted by shadowy creatures, who took a liking to the pirates' technology and moved to take every trooper they could.

The Pirate Troopers in Echoes are unique in that they have the capacity to teleport, an ability which they use to suddenly enter an area and attack Samus, though strangely they don't use during battle. In every other game this ability is reserved for high-ranking Pirates, such as Pirate Commanders.

Pirate Troopers appear in other areas around Aether besides Agon, but aren't very common and rarely respawn.

Pirate Grenadiers are Pirate Troopers armed with an experimental grenade launcher. The size of the launchers prevent Grenadiers carrying the scythes or beam weapons wielded by other Pirates; the launcher is also ineffective against nearby opponents. At close range, the Grenadiers will resort to ramming. Due to the time it takes to charge the launcher, Samus can easily get out of the grenades' blast radius. Samus first encounters the Grenadiers in the Space Pirate base in Agon after the first battle with Dark Samus. They also appear in the Temple Grounds on the way to Torvus Bog, but they do not respawn on subsequent visits. Along with the Pirate Aerotroopers, Pirate Grenadiers are the only Space Pirate varieties in Echoes that were not possessed by the Ing.

Dark Pirate Troopers are Darklings, Ing-possessed Pirate Troopers. They are a useful addition to the Ing Horde, as those who are trained to follow orders without question are easier possession targets. They're often placed in locations important to the Ing, such as Dark Portals. Ing also tend to target Pirate Commandos for possession, a unit which they greatly prize.

In Corruption
During the events of Metroid Prime 3: Corruption, Pirate Troopers got a major overhaul, using a new Phazon enhancement system. Their Phazon-powered weapons include an assault rifle and deployable energy scythe, along with EMP grenades for power-armored foes and a new Dash Jet system for increased mobility.

Corruption ' s basic Pirate Troopers mostly appeared on Bryyo, but they are seen every time the armor of an upgraded Trooper is broken off, implying that the Troopers from Echoes were armored too. They also appeared alongside Militia and Aerotrooper Units on Norion, and also frequently on the Pirate Homeworld.

The Troopers in this game seemed slightly less agile than before, but they could still jump very high. They were not seen to be able to cling to walls either, like the previous incarnations could.

Pirate Trooper varieties
Several types of Troopers exist in Corruption. Some of these units carry a portable battle shield that can either be removed with the Grapple Lasso or destroyed with Phazon attacks, except on Hyper Mode difficulty, provided the enemy has engaged Hyper Mode. The Grapple Voltage can also drain or overload energy from or into a Shield Trooper. However this can not be done in one go, as the Pirate will occasionally break free of the lasso. All of these varieties appear as Aerotroopers as well (excluding shield varieties).

Armored Pirate Trooper
Armored Pirate Troopers are equip with a standard armorsuit that provides adequate protection against beam weapons, but can be breached with missiles. These units greatly resemble the Pirate Troopers found in Echoes. While their heart-like feature in Echoes was a deep red, the one in this game is a light blue, to represent the Phazon corruption all the troopers bear.

Assault Pirate Trooper
Assault Pirate Troopers represent the best of the Pirate Troopers in the Space Pirate military. They are equipped with sloped, translucent orange, Missile-resistant armor. A Dash Jet system is also built into the armor. Basic armament includes assault rifles, energy scythes, and EMP grenades, all powered by Phazon. However beams can damage their armor.

Advanced Pirate Trooper
Advanced Pirate Troopers are Pirate Troopers which have been outfitted with a green-colored armor. The armor is weak against Missile blasts, but resistant to beam attacks. They are essentially stronger versions of Armored Pirate Troopers. Advanced Troopers also have a dash jet system, like many of the Pirate armor systems. Their weapon systems include assault rifles, energy scythes, and EMP grenades. These are the rarest troopers in the game, but are seen mostly during the Galactic Federation's assault on the Skyway to the Leviathan.

Trivia

 * A Pirate Trooper is shown fighting Samus in the startup video at the beginning of Metroid Prime Hunters, although there are no Space Pirates in the game besides the Bounty Hunter Weavel. This may suggest that Samus encountered them shortly before Metroid Prime 2: Echoes, due to the fact that Hunters is set between Metroid Prime and Metroid Prime 2: Echoes.
 * It would seem that the blue heart-like feature of the Pirate Troopers from Metroid Prime 3 was originally meant to be of a red color like their incarnation from Echoes. This can be seen at 1:09 of the following video, which shows an unused cutscene of Samus battling with a group of Pirate Troopers.
 * Interestingly, the official Metroid Prime website shows an image of a Plasma Trooper on the Power Trooper's description.
 * Gandrayda is seen using the form of a Pirate Trooper in several instances, and it is her only form to not have a known name. First, she disguises herself as a Trooper before attacking several in Generator C when Samus enters, and while she is dying after their battle, she morphs into the form of a Trooper. Space Pirate Data also mentions that she walks among them in their form, killing those who show the slightest bit of fear.
 * Metroid 1.5 shows a concept image of a creature called the Shock beast that is near identical to the Metroid Prime 2: Echoes Pirate Trooper, the only difference being the weapons carried.