Banshee

Banshees are synthetic-organic creatures derived from asari and mutated by Reaper technology. Frighteningly intelligent, Banshees are advanced pressure units usually found leading a Reaper strike force.

Banshees are created specifically from asari with active or latent predispositions to becoming Ardat-Yakshi.

Capabilities
Offensive

Banshees can charge their enemies (similar to a Biotic Charge) however, this charge only has a range of about five meters, so the Banshee moves quickly using a series of biotic "hops".

They also have the ability to grab people and subsequently impale them with their hands, resulting in instant death. They have a melee attack that involves the Banshee lifting its arms over its head and then swinging them down. This can completely deplete victims' shields and also stagger them. Sometimes they will stand still and briefly appear to charge up, after which they will scream and release a damaging and staggering biotic blast over a surprisingly large area. Finally, they throw powerful biotic projectiles (similar to Warp) that move slowly but track their target. Shields can be instantly destroyed and up to two health blocks are drained over time. On Platinum, this will drain all but one health block.

Defensive

Banshees can biotically "teleport" short distances to move quickly and unpredictably, which can make them very difficult to hit at range. They also possess highly durable barriers and armor. When under attack, they may create a visible shield that negates powers.

Tactics

 * Besides its deadly melee and shield depleting abilities, even a single Banshee will always have other faster moving units - if not heavy hitters - accompanying it, so be prepared to fight a mobile battle and aware of your surroundings so you won't be swarmed or flanked by other Reaper units.
 * While no less deadly, the Banshee's instant kill is the slowest to take effect. It can be interrupted (and the victim saved) if the Banshee is staggered by incoming damage (especially strong attacks like a sniper rifle shot from Tactical Cloak, a Biotic Explosion, or Sticky Grenades), or killed. Powers that have extremely high force ratings, like Throw, Biotic Charge, or Concussive Shot are also good at interrupting the attack.
 * When damaged after their barriers are knocked down, Banshees will sometimes drop to their knees and scream to regenerate. This scream does no damage, and is an opportunity to get in close for melee or shotgun attacks. This is risky however, as the Banshee can grab you.
 * Do not ignore the Banshee's ranged attack. While the biotic projectile can be dodged with some practice and the right timing (or sufficient cover), it is almost guaranteed to take down all but the strongest shields on impact, then afterwards take down at least bar of health. This can spell certain (if delayed) death if you're down to your last bar.
 * The health drain from the Banshee's Warp can be interrupted by any shield/barrier restoring power (i.e. Energy Drain, or the Geth Turret's and Supply Pylon's Shield Restore).
 * It's important to note that, unlike in Mass Effect 2, Overload does more damage to barriers than Warp. Of particular note is the Rank 6 evolution of Overload that doubles its damage to shields and barriers. Squadmates who can use Overload should concentrate on the Banshee to remove its barrier. After the barrier is depleted, Warp is better for wearing down the armor.
 * Some biotic powers will never be able to affect Banshees due to their lack of a health bar. Singularity, Pull, Stasis and Dominate can't affect a Banshee and will not leave an effect to be detonated.
 * Be wary about sticking to cover. They can rapidly close distance and grab you.
 * A Vanguard can successfully use Biotic Charge, but should immediately dive away from the Banshee to avoid its grab. This can be a useful tactic if combined with Warp on the Banshee beforehand to set up a biotic explosion.  The detonation will also stagger the Banshee, giving an extra fraction of a second to escape.
 * After unleashing the Nova/biotic blast attack, the Banshee will no longer be glowing. In this state, it is unable to either perform another biotic blast or teleport, making it the most opportune time to attack.
 * It is advisable to outright leave a Banshee alone and kill other enemies first: as long as you maintain good distance, it can't really do any lethal damage. Husks can grab and immobilize you for the Banshee to grab you. Ravagers can do the most damage in a single volley. Marauders and Cannibals should follow afterward.
 * Banshees have the highest chance to grab you when they are charging or glowing. Once they stop glowing, it's relatively safe to get closer. Once the Banshee starts screaming again, run away to a safe distance.
 * It takes a tremendous amount of damage from squadmates' attack to dislodge a Banshee's melee grab. Given the small window of time it takes for the Banshee to execute the melee-kill, it is wise to avoid it altogether.
 * It can be an efficient measure to combine the squad's powers. For instance choosing such powers as Reave, Dark Channel, and Overload can quickly take down its barrier.
 * In later multiplayer waves it is common to have at least one Brute in the wave with a Banshee, which is a very dangerous combination, so be aware of your surroundings thus avoid being boxed in.
 * Classes that chiefly use powers may consider keeping the Cobra Missile Launcher equipped when engaging Banshees to reliably save squadmates if they get grabbed.
 * A properly built krogan or batarian character can survive the Banshee's biotic blast attack without being staggered, giving them a perfect opening to attack with melee attacks while she recovers without risking impalement.
 * Human Vanguards with the Nova ability upgraded to give a bonus to cool-down and Biotic Charge upgraded to give back full barriers and to give a power damage bonus could kill a Banshee without having to fire a shot. If you Biotic Charge then immediately roll away, you can use Nova with the damage bonus while staying out of range of the Banshee's melee attack. If followed up with another Biotic Charge, your shields would completely recharge (if the Rank 6 Barrier evolution was chosen), allowing you to follow up with another Nova. If you complete the cycle enough times, you will kill the Banshee without using any ammo. It is important to note that in order for you to use this tactic effectively, you must have a high cool-down.
 * A Banshee's instant kill can be semi-interrupted if the player being executed is downed just before the player is grabbed. The execution animation will play out but when it is finished, the player will be downed and able to be revived. Similarly, if the grabbed victim is hit by other attacks that kill it prior to being impaled (for example, the Ravager's cannons or enemy grenades), the Banshee will drop the victim without finishing the impale and they can then be revived.
 * Combat Drones are invaluable at distracting Banshees, and though they will likely be destroyed quickly, its short recharge time means you can instantly cast a new one, keeping the Banshee occupied on something other than you and your allies.

Morinth
If Morinth was spared in 2185, she will appear during the assault on Earth as a Banshee. She will not behave any differently from any other Banshee and must be killed as normal.

Trivia

 * In The Art of the Mass Effect Universe and The Art of Mass Effect 3, Banshees are incorrectly stated to be asari matriarchs, instead of asari with Ardat-Yakshi potential.
 * The Banshee is a female fairy or spirit from Irish folklore, whose wails are said to be an omen of death. Similar creatures appear in Scottish, Welsh, and Norse stories.