Do Gatekeepers have any weaknesses that can be exploited?

Question

There are many types of deadly enemies in XCOM 2, but among the deadliest are Sectopods and Gatekeepers.

I used to be pretty afraid of Sectopods, until I discovered how many different items and abilities can completely wreck them:

1. EMP grenades/bombs bypass their thick armor, and do massive damage. They also have a chance to shutdown the Sectopod (for up to 2 turns?), and decrease its resistance to hacking (for 1 turn?).
2. Similarly, Blue Screen rounds can do massive damage to a Sectopod and lower its hacking resistance, though I think the round damage is mitigated somewhat by armor, unlike the EMP grenade. However, equipping the rounds on a grenadier with the shredder ability can get around this limitation very easily.
3. Combat hacker specialists can temporarily shutdown or take control of a Sectopod with their Haywire Protocol (made easier if a teammate first lowers hacking resistance with EMP grenades or Blue Screen rounds), or they can do massive damage with Capacitor Discharge, which acts like an EMP grenade. Additionally, with a fully upgraded Gremlin III, the Combat Protocol ability does a fair amount of damage (I think it was around 10-12) that bypasses armor (I think).

So, with all these different weaknesses, Sectopods aren't so scary for me to deal with anymore, especially if I shut them down for 2 turns with an EMP or Haywire Protocol.

My question is, do Gatekeepers also have any special weaknesses to certain items or abilities? They're very heavily armored, so of course bringing along a shredder grenadier and/or an Acid Bomb helps strip the armor off.

However, unlike the Sectopod, Gatekeepers can't be disabled for a few turns while you whittle them down, which leaves your squad vulnerable to its super deadly laser beam or AOE psi attacks. You could stall a Gatekeeper with a psi soldier stasis bubble for a turn, but that also renders the Gatekeeper immune to attacks for that turn.

Answer 1

EMP Grenades/Bombs

So I just learned from Are Gatekeepers vulnerable to EMP Bombs? that Gatekeepers can actually be heavily damaged from EMP grenades/bombs, and can even have a chance to be stunned by them for 2 turns!

I tested and confirmed this myself. In the following screenshot, I used an EMP Bomb on an undamaged Gatekeeper, and it took something like 12 damage, and was also stunned:

Which is weird, because you can't hack a Gatekeeper, so who knew it had robotic components that could be damaged by an EMP?

Flashbangs

I've heard that Flashbangs (or being disoriented) can lower a target's Will stat, which would make it more vulnerable to mind control. I decided to test this out too.

The following is the Will stat of an undamaged Gatekeeper versus a fully upgraded (i.e. has all abilities and fully upgraded Alien Psi Amplifier) Psi Operative using Dominate:

The target's Will is 110%, which reduces my chance to Dominate to 80%. After hitting the Gatekeeper with an EMP Bomb, followed by a Flashbang (so that it's also Disoriented), I checked the chances again, and the Gatekeeper's Will was still 110%.

I've also heard that Flashbangs (and being disoriented) can disable some of the Gatekeeper's abilities, but I haven't tested this out yet, and I'm not sure which abilities exactly would be disabled.

Answer 2

When they open (for a melee attack or mass ressurection) they lose most of their armour for one hit.

But better are psi attacks, the best is Dominate as you get them for the rest of the mission as it doesn't end like Haywire Protocol.

Null Lance will do a lot of damage, can't miss, and because they are 4 tiles it makes it easier to hit them and something else.

The single target psi attack also does about as much as a weapon shot would if they had no armour.

I believe Insanity would work on them but haven't tried.

Psi storm can rupture them making them take more damage

in the last mission with the avatar he can mind control them for a few turns, if you want to not have them mess up your ranks when that ends use statis when your avatars mind control is on T-1 cooldown and re control next turn

for other people you can equip AP rounds which peirce 5 armour, on a sniper or shotgun with laser sight this can do a lot.

In WAR suits the shred blast, plasma shot, and blaster bomb all remove a lot of armour.

Answer 3

From what I've seen Gatekeepers tend to travel with some fairly weak companions, so you can focus fire on them pretty heavily and largely neglect the rest of the pod (or kill the remainder with just a few actions). By the time you're encountering Gatekeepers you should hopefully have or be close to having plasma weapons.

There are a few options available to you:

Burst it down

With a psi soldier and some shredding ability, they're pretty easy to deal with in two turns:

• First turn - focus on shredding armor. A grenadier with Salvo is great here, because you can fire a grenade, then still shoot with Shredder ammo, or even fire a second grenade. Acid Bombs are great for shredding armor, but other grenades help too. After the rest of your squad has acted, have your Psi soldier use Stasis on it.
• Second turn - pile on damage. Sniper shots, Chain Fire, more grenades with Salvo, anything you can do. Your Psi Operative's Null Lance is very effective here, or you can try to apply Rupture so it takes extra damage. If it looks like you might somehow fail to kill it on the second turn, you can use Insanity on it. If you hit, you might get lucky and panic or Mind Control it. Even disorienting it will make it harder for it to run up and melee you, or use its powerful beam attack. (It may even disable its psychic attack, but I'm not 100% on that.)

As long as you don't miss too many shots, and you're not run out of grenades at this point, this is a pretty safe strategy.

Take it over

Despite having a powerful psychic attack, Gatekeepers are not that difficult to Dominate (roughly on par with Archons). Assuming your Psi Operative has been keeping busy you'll probably have a 70% chance to take it over. This is definitely a riskier strategy, because if it fails, you just lost your best option (Stasis) for keeping the Gatekeeper under control this turn. When it works, though, you get what is probably the best creature in the game.

Run away and spread out

If for some reason you can't try the above strategies - say, you don't have a psi soldier for some reason - you can try to minimize damage. Gatekeepers have three attacks:

1. A single-target beam attack for heavy damage.
2. A melee attack for medium-heavy damage which heals the Gatekeeper.
3. A psychic AOE blast (roughly 4-5 tiles radius) for medium damage.

If you have some room to run around, you can kite the Gatekeeper while taking shots. You want to be sure your soldiers aren't grouped too tightly. The ideal outcome of each turn is for the Gatekeeper to use their psychic attack on just one or two soldiers, because it opens their shell, reducing their armor for the first shot of your turn. You definitely don't want to leave anyone in range of the melee attack, or you're going to prolong the fight further.

This is definitely the riskiest strategy. It requires you to leave the Gatekeeper alive for a long time, hoping your cover is good enough to avoid getting shot. And since Gatekeepers destroy cover they move through, you're not going to have many good options to go back the way you came after the fight is over.

Answer 4

You could stall a Gatekeeper with a psi soldier stasis bubble for a turn, but that also renders the Gatekeeper immune to attacks for that turn.

Remember that you can attack first, and then use stasis as the last thing you do. I've dealt with many enemies just by dealing damage over multiple turns, preventing them from fighting back with stasis - sometimes chain-stasis from multiple psi units.

Answer 5

The other answers I can see suggest using EMP bombs as part of a more complicated strategy, such as making targets easier to hack. But if you just arm your squad with EMP bombs (2-3 will do the trick) they are effective on their own thrown in sequence in the same turn.

I generally equip 3-4 squadmembers with EMP bombs, making mechanical targets some of the easiest in the game to deal with. For example, a grenadier with Volatile Mix, equipped with an EMP bomb can take out a Codex (in all but the highest level) in a single attack that can't fail.

Works nicely with Sectopods and shields too.

Answer 6

Enemies tend to fight the soldiers they can flank. An easy way of dealing with them is to have 1 or 2 rangers with the untouchable perk and have those slaughter kill weaker enemies (first attack during enemy turn on this unit misses), and try to fool the gatekeeper in attacking these rangers. A gatekeeper will usually move, then do 1 attack, making that attack a guaranteed miss. Ideally the rangers move in deep, potentially even behind the gatekeeper. Rangers can easily can get very high accuracy ratings by moving close, and can almost always guarantee a kill by using rapid fire, even if the enemy dodges.

The psionic boom does not do a terrible amount of damage, and raises weak minions that could allow stalling for another round if necessary. Try to avoid placing soldiers over the corpses of previous enemies if possible to coax the gatekeeper in using the laser beam instead.

Now remove the armour using heavy weapons, then finish of with a double shot from a shotgun, or a combination of rifle and sniper rifle fire. Having holotargeting on a heavy weapon will make less of those shots miss too.

Answer 7

If there is a Berserker you can dominate, or have some other heavy hitter, and hit it when it's closed, they only do one damage but basically insta-kill them (only tested with Berserker so far)