Sentinel Guide (Mass Effect 2)

The Sentinel specializes in a combination of tech and biotic abilities. Due to their not being as proficient as an adept or an engineer in their respective fields, and lacking some advanced weapon training, the Sentinel is considered by most a "jack of all trades, master of none".



Overview
The Sentinel relies heavily upon tech and biotic powers both for offense and defense. The Sentinel arguably has the most survivability out of any class due to its signature ability, Tech Armor, and its ability to quickly incapacitate dangerous enemies. The Sentinel is the only class capable of disabling all three defenses: armor and biotic barriers with Warp, and shields with Overload. The Sentinel is also capable of crowd control using Cryo Blast and Throw. Its class Power of Tech Armor can double its shields and provide shock damage upon destruction. The main weakness of the Sentinel is its lack of weapons training, in that it is able to use only heavy pistols, submachine guns and heavy weapons (with the option of adding one extra class of weapons at a particular point of the game). All in all, the Sentinel is a versatile class that is capable of handling most situations, ranging from close quarters combat to long range, with its only notable weakness being heavily armored opponents.

For returning players, there are some major differences that need to be noted regarding Powers in general:
 * All Powers have been greatly simplified, either by condensing several of them into one or, in some cases, getting rid of them completely. Specifically, Sabotage is now included in Overload, the Sentinel's Barrier Talent has been replaced by the Tech Armor Power, Lift has become Pull, and Stasis has been removed to allow for more action-oriented combat.
 * The targeting system has been overhauled dramatically. Most biotic Powers travel in the direction of your crosshairs and can curve toward their intended targets, making it possible to hit foes behind cover. Others, such as Overload, will instantly affect their targets without having a travel animation.
 * All cooldowns have been reduced by a large amount, however, a global cooldown has been imposed: each Power, when used, not only activates a cooldown on itself, but also on all other Powers (equal to the cooldown of the activated Power).

Throw
Throw uses Mass Effect Fields to hurl targets away, damaging them if they hit an object. It can also be curved around objects and cover to hit its target. Throw really shines when used in conjunction with Pull, which reduces a target's mass, and thus allows Throw to launch foes against walls or over nearby ledges more forcefully. Throw also has an instant kill possibility: a frozen target Thrown at an object may shatter instantly. (Combining this power with the Sentinel's Cryo Blast is thus quite effective).

Throw is very similar to the Soldier's Concussive Shot. While it cannot affect barriers, it recharges faster, can arc around obstacles, and hits with greater force.

On higher difficulties (Hardcore and Insanity), Throw loses some of its usefulness as it is only effective against unprotected enemies. It is still useful, however, for throwing enemies off of ledges once they have been stripped of their defenses.

At rank 4, Throw can be evolved in two ways:
 * Heavy Throw: Adds a significant amount of momentum to the power with which enemies get hit.
 * Throw Field: Gives the ability to affect multiple enemies in a small area.

Warp
Warp spawns a Mass Effect Field that damages enemy targets and stops health regeneration. Warp can be considered the bread and butter of the Sentinel's biotic offense, perfectly reflecting the class as a whole: lots of applications, but with limited power. First, as mentioned, it stops health regeneration, making it very useful against krogan or vorcha. Second, it is potent against armor, although not to the degree of Incinerate, and against biotic barriers. Lastly, if the target is affected by another biotic ability, such as Pull or Slam, it will detonate the target, causing damage and knocking back enemies near the target.

Shepard's Warp is somewhat different from his squadmates' version in that Shepard's Warp travels in an arc and can bend to home in on its target, while the squadmates' version hits directly on the location marked by the Shepard's crosshair. It is advisable to learn to throw Warp's "bolt" in a curve to hit enemies behind cover.

Warp is very useful on higher difficulties, where many enemies are protected by at least a thin layer of armor, and others have both armor and biotic barriers. It is notable that the Warp explosion damages all enemies, even when they are protected. Thus, a viable tactic on higher difficulties is to quickly strip an enemy of its defense, Pull it, and then detonate it with Warp. In order to quickly strip enemies of their defenses at these difficulties, Heavy Warp is often the better option of Warp's two evolved forms, because of its greater damage.

At rank 4, Warp can be evolved in two ways:
 * Heavy Warp: Warp damage is hugely increased.
 * Unstable Warp: Increases the blast radius when Warp detonates biotic effects.

Tech Armor
The power generates an energy armor suit that boosts the user's shields. Considering that most enemies will be much more attracted to the Commander than your squadmates, having a powerful, unique defensive power really gives the Sentinel an edge on higher difficulties. Once activated, the armor remains active until it is destroyed or upon exiting a combat zone or loading a game (even if Tech Armor was active at the time of the save). On occasions when it does get destroyed, Tech Armor sends out a pulse of energy, knocking back and damaging nearby enemies within a certain radius of the Commander. This reactive damage is very useful when facing melee enemies such as husks or varren, especially since they are found in swarms.

At rank 4 it can be evolved in two ways:
 * Assault Armor: Greatly increases the power, range and damage as well as providing a shield boost when it is brought down.
 * Power Armor: Further increases shields as well as providing a damage bonus to all your powers.

Overload
A very useful multi-purpose ability, it's also the other defense-disabling ability available to the Sentinel. Overload focuses on shutting down enemy shields, damaging synthetics and from rank 3 onwards, overheats weapons. It can also be used on explosive canisters and flame-throwing enemies in order to make them combust and explode. At higher difficulties, Overload will be Sentinel's bread and butter attack as most enemies are protected with shields. Due to the tendency of enemies crowding close to each other, Area Overload is usually the better option in higher difficulties: the stun effect (to synthetics) and the weapon overheating can affect several enemies at once.

At rank 4, it can be evolved in two ways:


 * Heavy Overload: The damage of the Overload is greatly increased, with an added potential that if the Overload killed a synthetic, it would explode upon death, damaging all other enemies nearby.
 * Area Overload: Increases the pulse strength to cover a wide area, making it easy to hit multiple targets.

Cryo Blast
When activated, the user's Omni-tool fires a mass of super-cooled subatomic particles capable of snap-freezing targets within a certain radius. Cryo Blast is the only crowd control ability available to the Sentinel, and it can curve over cover to hit its target. While the enemy is unable to act during the cryo freeze, safe shots can be fired without fear of retaliation. Frozen enemies are also more susceptible to direct damage and can shatter when their health is low enough. However, any sort of armor, shielding, or barrier prevents the target from being affected, meaning this power loses some of its usefulness on higher difficulty levels. Also, frozen enemies have a tendency to fall behind cover, thus making it difficult to finish them off. Throw can be used instead to counter enemies such as krogan, varren or husks who may be charging at you (once the enemy's defenses are down).

At rank 4 it can be evolved in two ways:
 * Deep Cryo Blast: The potency and duration of the power is enhanced greatly.
 * Full Cryo Blast: Expands spray area to maximize the chances of freezing multiple targets.

Defender
The class ability of the Sentinel augments its most important attributes. Defender reduces the cooldown timer on Powers, increases Shepard's health and gives a negotiation bonus by boosting Paragon and Renegade points. In its Raider evolved form, it also boosts Power damage.

Both of Defender's evolved forms have advantages depending on play style: aggressive Sentinel players may prefer Guardian since Shepard can use Powers more frequently, while those with a more "artillery" style of play might find Raider (along with Power Armor) to be a better option.

At rank 4, Defender be evolved in two ways:
 * Guardian: Provides the greatest bonus to Power recharge time and Paragon/Renegade scores.
 * Raider: Gives a damage bonus to all your abilities and a lesser amount of improvement to Power recharge time and Paragon/Renegade scores.

Bonus Power
The Sentinel can be played in a multitude of different ways. With this much freedom choosing your bonus talent can create a variety of different builds.

Armor Piercing Ammo / Warp Ammo
As a Sentinel, you'll be constantly using your other powers, so taking a passive ammo power such as Armor Piercing Ammo or Warp Ammo will benefit you greatly, especially if you lack a teammate with squad ammo. Armor Piercing Ammo has more damage potential (+70% weapon damage vs. health and armor), while Warp Ammo has greater versatility (+50% weapon damage vs. health, armor and barriers). Warp Ammo also does double damage against enemies affected by biotic attacks, such as Pull or Singularity. As a Sentinel already has abilities that are effective against barriers, the choice between Armor Piercing Ammo and Warp Ammo is a matter of personal preference.

Reave
Reave is a very useful bonus power, as it is effective against barriers, armor, and health, and it also stuns unprotected organics while giving a bonus to health regeneration. While Reave may seem somewhat redundant due to the Sentinel's access to Warp, you may want to take this power instead of Throw and Warp in order to free up room for Cryo Blast.

Geth Shield Boost / Barrier / Fortification
These Powers provide bonus to a Sentinel's shields. Barrier (biotic) and Geth Shield Boost (tech) are the recommended options, and are the same except for their Improved variants: Barrier lasts three times as long (a non-factor for use during combat), while Geth Shield Boost grants a 10% bonus to weapon damage. Their Heavy variants increase the shield boost from +75% to +100%. With proper timing, you can keep restoring your shields to full before enemies can deplete them. Unlike Tech Armor, these Powers do have a time limit, so when restoring your shields to full, make sure to activate your bonus Power rather than Tech Armor. (Note that when these Powers are used in conjunction with Tech Armor, only Tech Armor will have a visible effect, even though the bonuses do stack.)

Energy Drain
While the Sentinel already possesses a means with which to disable shields (Overload), the Energy Drain power allows a setinel to restore a portion of the enemy's shield to their own. This can be very useful coupled with Tech Armor, allowing the Sentinel to recharge some of their shield instantly without having to rely on a defensive skill with lengthy cooldown.

Flashbang Grenade
Flashbang Grenade combos with the Sentinel's robust shield-breaking to give an option to shut down packs of enemies pre-emptively, as it works against enemies protected by Armor. The Improved Flashbang Grenade evolution, in particular, gives a very wide zone of crowd control with a pretty quick cooldown. Flashbang is of special note to a Sentinel who took Shotgun specialization, as the affected foes drop to the floor, allowing them to be easily executed with a shotgun blast. In addition, because it is a Tech type power, it benefits from a sentinel's class power.

Weapons
Heavy Pistols, Submachine Guns

M-12 Locust Submachine Gun
If the Kasumi - Stolen Memory DLC is installed, players can have acess to the M-12 Locust Submachine Gun. The M-12 Locust can be found during Kasumi's loyalty mission in Donovan Hock's vault on the table with the graybox.

Since the Locust has high accuracy and high damage against armor, acquiring the assault rifle as an advanced weapon training for Sentinels is no longer mandatory. When compared, the M-12 Locust has a higher DPS rating than the M-8 Avenger, Geth Pulse Rifle and Collector Assault Rifle at almost the same accuracy level. The M-15 Vindicator has higher DPS but much lower total thermal clip capacity. Players can now choose proficiencies on sniper rifles or shotguns safely for a varied gameplay experience.

Weapon Specialization
Any of the three bonus weapon training options can be a good choice for a Sentinel, depending on play style. Sniper rifles are perhaps the best complement to the Sentinel's existing abilities, offering the ability to kill enemies beyond the range at which powers can normally lock on, extending that distance while using the sniper zoom, and also providing excellent damage versus armor with the AP sniper rifle upgrade. A Sentinel with a sniper rifle can deal with any enemy, anywhere on the battlefield. On the downside, it might seem a bit awkward when using powers while equipped with a sniper rifle, for the visual is locked into the rifle zoom while the power bolt travels to its target.

Assault rifles deal high damage at mid-ranges, and are a good all-around choice for any character, including a Sentinel. If an assault rifle is chosen, the M-15 Vindicator is probably the best one to carry; while its ammo supply is limited, it is more effective at range than the M-8 Avenger. On the downside, the fire-rate of Vindicator is low, and without Adrenaline Rush, it's hard to get the precision the Soldier class can achieve with this weapon. The Sentinel might be better off with spraying bullets than trying to get a precision shot at mid-range. The Geth Pulse Rifle can also make a good choice as it is extremely effective at stripping shields and barriers, though its overall damage is rather low.

Finally, shotguns can synergize with Tech Armor, especially the Assault Armor variant, which makes it easier for a Sentinel to approach enemies within an effective range, knocking them down and leaving them open to a point-blank shotgun blast. In the higher difficulties, however, this is not a viable option. Without the Soldier's Adrenaline Rush or the Vanguard's Charge, the Sentinel will be hard pressed when trying to retreat from a CQC. However, the Geth Plasma Shotgun added in the August 3, 2010 Firepower Pack DLC is one of the best weapons a sentinl can use, due to its long range and powerful charged shot, which a sentinel has adequate time to use frequently due to the protection of Tech Armor.

Upgrades
The top priority should be given to tech and biotic damage upgrades, for these are the main modes of attack for a Sentinel. You should spend your credits to max out these upgrades. The second priority is shield and health upgrades, this will augment the strong point of a Sentinel even more. The third priority is SMG upgrades. Make other upgrades when resources allow to do so. For armor accesories, buy the ones that augment shield or powers. Sentry Interface and Umbra Visor are both desirable, depending on your play style and preferences. Stimulator Conduits is also a great choice: it's always nice to be able to run faster in both offensive and defensive maneuvers.

Squad Selection
Sentinels are effective against all types of defense (armor, barrier, and shields). This affords characters of this class a great deal of flexibility in selecting their squadmates. Any combination of team members can be chosen without exposing the squad to any particular weakness, and the most effective teams are usually tailored to fight a specific type of enemy.

Anti-Armor
Enemy barriers and shields fall quickly to the Sentinel, leaving unprotected/heavily armored enemies to be dealt with by the rest of the team. Squadmates wielding assault rifles (Garrus, Grunt, Legion, Samara or Zaeed) are a good fit for most missions, as is Mordin who can burn through enemy armor with Incinerate.

Squad Ammo
Sentinels initially lack any ammo powers of their own; therefore, it's usually a good idea to bring along someone with a squad ammo ability to empower the entire team. Like the Sentinel class itself, Jack's Warp Ammo may be a good choice as it is effective against both Biotic Barriers and Armor. Zaeed's Disruptor Ammo ability is effectively Overload as an ammo power, and when evolved into squad ammo it can make the whole team more effective against shields and synthetic enemies. The Disruptor Ammo may be a life-safer when facing Geth Hunter and Geth Prime. Armor Piercing Ammo from Garrus is effective against, well, armor but has no ability to make organics panic. The Shredder Ammo from Thane is effective against unproctected organics, but loses its effectiveness in higher difficulties where nearly every enemy is protected. The Incendiary Ammo power from either Jacob or Grunt is better suited to most situations for it provides bonus against armor, stops health regeneration and panicking organics (including the Collectors, but not husks) when their protection has been stripped away.

Complementary Powers and Specialization
Miranda can be a good choice for any type of mission. Her Warp and Overload powers will assist the Sentinel in quickly overcoming enemy defenses, and her Cerberus Officer ability provides bonuses to the entire squad.

With access to both Warp and Throw, a Sentinel is capable of inflicting biotic combos on enemies if partnered with the proper squadmates. This is easiest to accomplish with Jack, Jacob, or Samara using Pull. It is also possible with Miranda's Slam, but requires more precise timing.

The team's tech specialists, Legion and Tali should not be overlooked either. With their AI Hacking and Combat Drone powers, they can often damage enemies while effectively drawing fire away from the squad. Legion, armed with an assault and sniper rifle, should be selected for his superior weapon damage, while Tali may be preferred against synthetic enemies for her Energy Drain, which effectively mimics Overload. A word of caution: both Tali and Legion are not strong in the health department and may fall quickly if the enemies focus assault on them.

For combat, a Sentinel needs a mid-to-long range shooter backup. Thane (with Warp and sniper rifle) is a good complement if you can find a spot for him to hang back and snipe. Better still are Garrus (with Concussive Shot and Overload, and both assault rifle and sniper rifle) or Grunt (with researchable 50% health bonus, health regen via Krogan Berserker, and Assault Rifle). The best might be Zaeed (with a 50% bonus weapon damage, assault rifle and sniper rifle). To some extent, Legion is also useful for it is the only squad mate capable of using the M-98 Widow after upgrade.