N7 Shadow Infiltrator

These soldiers are the go-anywhere, fight-anything special forces of the Alliance that were trained at the Interplanetary Combatives Academy in Rio de Janeiro, Brazil. They had to survive combat situations "in an admirable and effective fashion" to receive the N7 rank. Many N7s now train other species in anti-Reaper asymmetric warfare.

Shadow infiltrators use implants to dramatically improve agility, making them slippery combatants on the battlefield. Their monomolecular blades are a menace from cover and close range.

General Notes

 * Primarily, a Shadow's specialty is to quickly eliminate dangerous or hard to reach enemies while the rest of the team deal with the main force. Key targets include Geth Rocket Troopers, Nemeses, Phantoms, Ravagers and Turrets.
 * When using Shadow Strike, you will cloak and move behind the opponent, even if they are at range. This essentially turns Shadow Strike into an Infiltrator's Charge, allowing unsurpassed mobility around the battlefield. Shadow Strike can also be rank evolved to provide either; damage reduction or shield drain evolutions of the power. Couple this with the fact that the N7 Shadow Infiltrator can cloak, and a player can: select targets while shielded from enemy sight, Shadow Strike (which is a melee class attack and as such could couple cloak damage bonuses and dual power use evolutions at rank 6), and return to cover before the target (if still standing) is alert to the player.
 * The rank six shield drain evolution of Shadow Strike will make the N7 Shadow significantly more durable in combat. It functions in a similar manner to Energy Drain; when performing Shadow Strike on a shielded opponent, you will absorb their shields, restoring your own. Unlike Energy Drain, it will not restore shields when used on unshielded synthetics.
 * The Shadow ranks a conditional 3rd in heavy melee damage, behind the Batarian kits. While the Shadow's sword strikes are slower than the N7 Slayer, they can potentially be more damaging depending on how Sword Mastery is built and what enemies are being engaged. If Sword Mastery is built for extra Armour/Shield damage, the Shadow will do more melee damage to respective Armoured/Shielded enemies than the N7 Slayer. Adding Tactical Cloak bonuses further improves this advantage.
 * With Sword Mastery maxed out in favor of heavy melee damage, and Shadow Strike maxed out in favor of damage, it is possible to kill almost every single enemy in one hit (on Silver) if used with Tactical Cloak. This is true even without the rank 4 Tactical damage evolution. Even Phantoms can be instantly killed in this manner. This makes duration a much more appealing option at rank 4, since the Shadow is far better at close range than any other infiltrator.
 * The bonus power evolution of Tactical Cloak is extremely useful for the Shadow, as it allows two Shadow Strikes to be performed before uncloaking (and therefore benefit from the Cloak's damage bonus twice). This allows the cloaked Shadow to dance around the battlefield, taking at two enemies in each cloak. Alternatively, she can cloak, take out a target with Shadow Strike, then return to safety while still cloaked. This gives her some great mobility options for getting out of tough situations.
 * The Shadow performs best when geared around melee damage and power use. For these reasons, a light load-out is recommended.  With the massive damage of their melee attacks, the sheer lethality of Shadow Strike, and the decent crowd control ability Electric Slash, they are well suited to complete a match without firing a single shot.
 * If the Rank 5 Electrical Damage evolution of Shadow Strike is taken, players can detonate it with Electric Slash to create a Tech Burst single-handedly. This is useful when engaging large enemies who will still be alive after the former - execute a Strike, quickly dodge behind cover, then activate the Slash. The brief vulnerable period is largely irrelevant since Electric Slash can hit enemies behind solid objects.
 * As always, caution should be exercised when engaging Banshees, Brutes, Atlases, Phantoms, Scions, and Praetorians at close range, in order to avoid their insta-kill moves.
 * The rank 4 damage reduction evolution of Shadow Strike can greatly increase your survivability after uncloaking, allowing you to shrug off 40% of all damage for five seconds after performing Shadow Strike. This lets you survive in heated combat until cloak is off cool-down.
 * As with Kasumi's power in Mass Effect 2, Shadow Strike can be a useful distraction. Using it on a powerful enemy will get its attention, causing it to turn around and redirect its fire from the player's teammates. A nimble player can dodge the retaliatory strike and escape into cloak, though this is a risky maneuver.
 * While shotguns combine well with Shadow Strike for a close quarters specialized character, equipping a lightweight sniper rifle is also an excellent choice. The resulting character is strong at all ranges, with melee attacks and Shadow Strike (with a short cooldown) covering short-range combat, and the rifle covering long range. A sniper rifle's scope also allows the player to lock onto enemies for Shadow Strike from further away.
 * For a completely Shadow Strike-oriented Shadow, to retain a cooldown reduction of 200%, a heavy pistol is an excellent choice. With this play style, you are unlikely to fire your weapon, so damage is irrelevant. What is important, however, are the Melee Damage and Scope mods. This gives you even more damage output and a longer range for Shadow Strike at no cost to your power recharge. Alternatively, you could equip the Disciple and an omni-blade attachment for a close quarters edge as well as up to 50% more damage in hand-to-hand combat. It'll drastically increase your effectiveness against almost any foe, but at the cost of +50 weight, possibly causing you to have less than 150% cooldown.
 * The Armor Damage evolution of Sword Mastery is an excellent choice, as it allows the Shadow to be good at what it previously lacks - dealing with armour. Both shields and barriers are devastated by Electric Slash and Shadow Strike but armour remains stubborn without this evolution taken. Alternately, the Shadow can carry a weapon such as a sniper rifle or the Carnifex that is effective against armor.
 * The Shadow is capable of using Shadow Strike twice, at 200% CDR, if Bonus Power Cloak is taken but the window of time available requires extreme precision and an instant jump to a second target; Shadow Strike followed by Electric Slash is impossible. To improve this, the 4th Evolution of Tactical Cloak, Duration, is an ideal choice. The window of time available for double Shadow Strike gives you time to choose your second target or escape if you must and Shadow Strike followed by Electric Slash becomes possible, for Cloaked, high damaging Tech Bursts.
 * It's possible to replace Tactical Cloaks' cooldown timer with Electric Slash by cancelling Tactical Cloak manually right before using Electric Slash itself. This essentially swaps the two powers' respective cooldown timers, as Electric Slash is done last. Due to Electric Slash' extremely low cooldown, this is extremely useful as it allows the Shadow to get Tactical Cloak back up extremely fast, or even allow a player to simply reset it if the duration is running low. This can also make it so rapid use of Electric Slash, or the Shadow Strike to Electric Slash combo as noted above, can always be done in stealth or minimize exposure respectively.
 * An Avenger X goes extremely well with the N7 Shadow if your better weapons are still at level 1 or if you've yet to unlock better weapons and mods. Without any ranks in the "N7 Shadow" class, your power recharge rate will be 180%, with rank one increasing that to 190% and rank four increasing it 200%. The Avenger X has better accuracy and stability than even the Locust SMG (which has high accuracy for an SMG) while retaining solid firepower. It will also be lighter than most SMG's without the Ultralight Materials mod.

Cerberus

 * Shadow Strike is usually effective against Guardians -- since the Shadow appears behind the target, the Guardian's shield is useless. However, sometimes the Guardian will be aware of the Shadow, and will turn to interpose his shield in time.
 * Properly specialized, a double Shadow Strike from cloak (bonus power allows two to be used before cloak is removed) with melee damage bonuses will kill a phantom full health and barriers even on gold.
 * Even without the highest-damage Shadow Strike specialization, Shadow Strike is extremely effective at killing Phantoms. With the electrical damage evolution, the Phantom will continue to take damage over time, allowing her to still be targeted when she cloaks, and Shadow Strike has essentially perfect accuracy, allowing it to connect even if the Phantom is running or dodging. Make sure to dodge away after performing Shadow Strike, though, as the Phantom will perform a retaliatory strike even if the player is cloaked.
 * It is very important to ensure that the Phantom is not aware of the Shadow when executing Shadow Strike or the Phantom will immediately counterattack, leaving the Shadow highly vulnerable and in critical condition. If the Phantom is aware of the Shadow prior to performing Shadow Strike, the Phantom may, on occasion, interrupt the Shadow Strike with her instant-kill attack, killing the Shadow before the blow even lands.

Collectors

 * Using Shadow Strike on an Abomination (and thus killing it) will cause it to immediately explode, inflicting a lot of damage. For this reason, using Shadow Strike on Abominations is not recommended, especially if it is Possessed.
 * Shadow Strike is more effective against Collector Troopers and Collector Captains. If you evolve Shadow Strike and the Sword Mastery classes to do max damage, you can get rid of these enemies in one strike. If they are Possessed, you'll still do plenty of damage.
 * Electric Slash can be used to get rid of Seeker Swarms or Seeker Plagues without getting close.
 * Because Scions are very slow to react, Shadow Strike can be very useful on them, especially when evolved to do max damage to armor.
 * A good note to remember is that if you decapitate an Abomination, it will not explode. So if you maximize melee damage, along with a weapon mod that increases melee damage, one never has to worry about dodging their post-mortem explosions.

Geth

 * With Geth, using shadow strike on enemies is not as risky as it is with the other factions, since Geth do not have any units that can instantly kill you. However, since all Geth possess the ability to stagger a player, getting caught in the middle of a cross-fire after using Shadow Strike can be a grave mistake.

Reapers

 * When using Shadow Strike on a Ravager, be sure that you will kill it and whether or not you do, be ready to Dodge backwards as soon as you are able, otherwise you are going to be assaulted by Swarmers or be quickly damaged by the blood, something you simply cannot afford.
 * It is recommended to wait until the Ravager is preoccupied with shooting before using Shadow Strike or it will rupture its sacs and cause massive damage. Alternatively, one could deliberately shoot all of the Ravager's sacs before performing a Shadow Strike.
 * Brutes are an excellent way to test your capability to Shadow Strike. Always wait for a Brute to charge before you initiate your combo and Shadow Strike just before it reaches you. That way, you will teleport behind the beast and strike him from behind where he takes maximum damage.
 * Shadow Strike may be safely used against Banshees if they are in the early stages of a teleport chain. Shadow Strike will often position the Shadow a few jumps before the current location of the Banshee to slash at nothing. Despite the apparent miss, the Banshee will still take full damage.