Praetorian

The Praetorian is a slow-moving flying Collector construction which appears in Mass Effect 2. It consists of thirty deformed Husks fused together, and has a strong barrier and powerful armor (acting as its health), giving it high durability. Commander Shepard engages a Praetorian on two occasions: once at the end of the mission on Horizon, and once during the escape from the Collector Cruiser. Several Praetorians were also involved in the attack on the Normandy SR-2.

Capabilities
Offensive

The Praetorian attacks in two different ways:
 * Particle Beams: When the Praetorian is hovering and has a clear shot, it will fire its particle beam towards its opponent for about 3 seconds, followed by 2.5 seconds of cool-down time. It only takes a couple of seconds of exposure to this weapon to kill Shepard.


 * Death Choir: A ground attack followed by an area effect attack: first, the ground strike knocks the Praetorian's opponent back for about a second. After that, there is only a short period of time left to run away from the area-effect attack, which is likely to cause an instant death. The ground strike is triggered if an opponent is within range of the attack or if the Praetorian's barrier is depleted and its armor has taken a threshold amount of damage (typically when its armor reaches 3/4, 1/2 or 1/4 strength). Note: The Praetorian is invulnerable during this attack. After the attack is complete, its barrier will be fully recharged.

Defensive

The Praetorian has extremely strong armor. At first sight it has no barrier, but the Death Choir gives it a biotic barrier, which recharges after each Death Choir attack.

Tactics
General Tactics
 * Before the fight, be sure to equip all of your weapons with Armor Piercing Ammo, Warp Ammo, or Incendiary Ammo, if available. Warp Ammo is ideal, but Armor Piercing Ammo is preferable to Incendiary. If you have both Warp Ammo and one of the others, you may wish to equip half of your weapons with each, using Warp Ammo on the Praetorian's barrier and the other type when its armor is exposed. Heavy Weapons are also extremely useful. The M-9 Tempest SMG is particularly effective at dealing with the Praetorian's barrier, as it can be used at medium to medium-long ranges on full-auto due to the Praetorian's large profile. Shotguns are discouraged as their shorter engagement range leaves you potentially exposed to the lethal Death Choir attack, but they can still be useful.
 * During the actual fight, Shepard is typically the only opponent the Praetorian follows and the only target of its particle beam. However, your squadmates can trigger the ground-strike attack. The Praetorian will constantly move towards Shepard, apparently trying to find a chance to use its ground-strike attack. During this fight, it is ESSENTIAL to keep mobile. Take cover when you can, as it will protect you from the particle beam attack, but if the Praetorian gets near enough to use its ground-strike attack, you'll be in a very sticky situation. Your team-mates' location isn't really important, just set them both to attack the Praetorian and use Unity whenever they "die".
 * A good tactic is to run backwards around an object whether it be a pillar, vehicle, etc. The Praetorian will not fly over the object and will continue firing into the object, so this is the safest way to stay alive.
 * Praetorians are immune to Stasis.

Class Specific Tactics As a Soldier, equip yourself with the M-920 Cain because on Insanity difficulty a hit will leave the Praetorian with 25% armor, but by the time you get your senses back, it will have restored its barrier. Use Concussive Shots to deal with the barrier and a Widow sniper rifle with Incendiary Ammo will deal very decent damage to its armour as well. Try to stay as far away from the Praetorian as possible and snipe or use Concussive Shot on it as quickly as possible. Once the barrier is down, use Adrenaline Rush to get as many shots in as possible. Incendiary Ammo is useful once the barrier is down. If you keep your distance and make sure to keep your squad out of the ground attack's range, the fight should be over pretty quickly. If you see the Praetorian getting too close, use an Adrenaline Rush to get away. Having Garrus on board is also convenient, as his Concussive Shot helps take down the barrier much quicker. Warp-wielding squadmates are also effective against its barriers and armour. On Any difficulty Warp Ammo is very useful, quickly taking down it's barrier and dealing effective damage to it's armour. On Insanity difficulty using Jack with Squad Warp Ammo is preferable to choosing Warp Ammo as a bonus power. An overcharged shot from a Geth Plasma Shotgun, armed with Warp Ammo, will rip its barrier apart. A Revenant with Warp Ammo is useful for both the barrier and armor and is even more effective against the Praetorian's armor due to its high armor multiplier. As a Sentinel or Adept, both of the Praetorian fights offer areas of the map that will allow you to circle behind objects to keep you permanently safe from the Praetorian. On Horizon, there is a truck in the top-right corner (from your entrance) that you can circle while launching Warp attacks around the truck, thus keeping you safe from the Praetorian while you and your team whittle down its barrier and armor. On the Collector Ship, there is a pillar off to the left side (from your entrance) that you can circle while launching Warp attacks around the pillar, again keeping you safe from the Praetorian. While neither of these tactics end the fight particularly quickly (you might want to use the Cain first), they will keep you safe as the Praetorian attempts to maneuver around these obstacles while allowing you to launch attacks. As an Infiltrator, you have the ability to use Tactical Cloak to keep out of the Praetorian's sight, which will cause it to ignore you for a few seconds to focus on your squad. If one of your squadmates is on the other side of the battlefield, by the time your cloak runs out, the Praetorian will have given you plenty of room to maneuver and a clear shot as it turns around (especially useful on the Collector Ship if you chose the M-98 Specialization). Use Submachine Gun fire (preferably with Warp Ammo) to take out the Praetorian's barrier before following up with Sniper Rifle or Heavy Weapons against its armor. Once the Praetorian is focused on you, your squadmates will have some time to recover before you reactivate Tactical Cloak and repeat the process. Essentially, you're playing ping-pong with your squadmates, using the Praetorian as the ball. This is best done with durable squadmates who have Concussive Shot, like Grunt or Zaeed, who can also deal with any other nearby enemies such as Husks or Collectors, but any squadmate will work if they have enough health and/or cover to survive a shot from the Praetorian's particle beams. This will be the toughest fight against the Praetorian as in Insanity, you must not only deal with the fact you are lacking in health but also the fact Charge is useless against the Praetorian. The major advantage you have over the Infilitrator is the Incendiary Ammo which allows you to cause Husks and Collector Drones to panic. Squad powers are even more important than the other classes as you should bring someone with Warp to weaken the barrier/armor down. Charge can be used to temporary delay the Praetorian from attacking you and allow your squadmates to finish their power cooldown while you defeat the Praetorian with the M-300 Claymore or Heavy Weapons.
 * Conditions: Insanity, Soldier, M-98 Specialisation or M-76 Specialisation
 * Conditions: Insanity, Sentinel or Adept
 * Conditions: Insanity, Infiltrator
 * Conditions: Insanity, Vanguard

Trivia

 * The Praetorians are likely named after the Praetorian Guard, a force of bodyguards used by Roman Emperors until the fourth century AD.
 * The Praetorians can also engage their enemies in close combat, using sword-like extremities to tear them apart, which is shown during the attack on SR-2 Normandy.