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Evolves From: Spitter
Evolves To: N/A
Role: Bring the Hive's ranged combat castes to their maximum potential with long range acid glob shots, allowing you to bombard and heavily damage areas after a bit of setup. Use your enhanced vision to locate targets without being seen and shot. Use your acid lance for close range defense. Use your incredibly strong acid to make short work of everything in your way.
Guides: The Guardian Caste Guide

General Information

The Boiler is the evolved form of the Spitter and perhaps the ultimate ranged warrior of the Hive. It is a slow and weak large Alien with a somewhat weak attack, trading the Spitter's old role on the battlefield with a special, almost Support-like role. It is otherwise relatively average, with a decently large plasma pool that should not pose any issues, as the Boiler will be always set up in weeded backlines. It does however get the strongest Corrosive Acid in the game, making short work of anything the Boiler can physically get up close to.

With an unique ability to Bombard the battlefield with massive Boiler globs, the Boiler is akin to artillery, capable of standing back and whittling down anything it is aiming at. The Boiler has two types of acid launch. A 5x5 AoE attack, that takes a bit of time to fire, and all marines can see where it will hit. And a second acid attack, which is acid lance. You can move while charging it (which takes very little time) and then launch it in a rough line, dealing decent burn damage to anyone hit by it.

The Boiler is also blessed with Enhanced Vision, allowing it to zoom outwards in the direction it is facing. It is obviously critical for its role as a Support caste, and allows it to keep a safe distance from whatever it is bombarding. If it is ever caught at close range, it still has one last desperation attack in the form of an Acid Lance, that will deal decent burn damage, but cannot stun.

Another of the boiler's abilities is to Dump Acid. This puts all abilities on cool down, while granting you a higher movement speed, and putting a tile wide cloud of gas over every tile you pass over.

Worth noting is that the Boiler's acid reserves causes him to be uniquely bioluminescent, which might compromise its own stealth in most situations. This acid will also be released as a small gas cloud when killed, although it is probably not a desirable use of a Boiler and T3 slot.

Playing as a Boiler

With all of its abilities, it is patently obvious that the Boiler is meant to stand back and bombard its targets, often accompanying the majority of the Hive in their pushes or defensive holds. It is fairly common for them to set up as far away from their target as possible, usually ten tiles or more. Beware that you will need an unobstructed line of fire between you and your target. Any solid structure other than see through structures will block you fire. You can shoot through windows and resin membranes. You cannot shoot through walls.

The acid gas attack will show up as yellow circles, then take a few seconds, then turn into the gas. This lets marines know to get outta there, so it is good to gas targets that cannot move fast, are stunned, or cornered. It deals meh damage even if it is just activated on someone and they escape. If you are in the gas for the full duration, chances are high that you will die.

Getting cornered at close range is a nightmare scenario for Boilers, but you still have a few desperation tactics to work towards an escape. First of all, always be aware of approaching Marines. You can dump acid, disabling your abilities to get outta there fast, and leave gas behind you in a trail, while speeding you up. If that is not enough and you find yourself in close proximity to raging tallhosts, use your Acid Lance tactically to cover your retreat. It ought to dissuade them and allow you to run. Don't attempt to kill them yourself, your slash is weak and your health pool is fairly minuscule for a Tier 3 Alien. If you do die, you'll explode in an acid cloud as a last resort.


Abilities: Description:
Xeno Rest.png
Used to rest and get up. Xenos heal faster when resting on weeds.
To devour, grab a host with Ctrl + Click or Grab intent (3 in hotkey mode) then click yourself, standstill. To stop the host from getting up and running away, you can switch to an empty hand (X in hotkey mode) and keep tackling them using Disarm intent (2 in hotkey mode) when you are devouring them. Xenos with devoured humans inside them can not vent crawl but Xenos with devoured monkeys can. Hosts with boot knives can injure the Xenomorph they are inside if they are conscious. (Edit this template)
Corrosive acid.png
Corrosive Acid
Vomit a glob of acid on item to dissolve it. Multiple items can be clicked at once as long as you are standing still. The cost of plasma is increased compared to other castes due to how the boiler has stronger corrosive acid.

Costs 200 plasma.

Artillerist PASSIVE: Whenever you increase your sight range, you have a 'buffer' of 7 tiles to move before the your view range increase is cancelled.
Toggle Long Range Sight.png
Toggle Long Range Sight
Use "Stretch to fit" to minimize the hassle of changing icon size when zooming in/out.
Toggles long range sight in the direction you're facing.

Costs 20 plasma.

You dig in and prepare to fire, to fire a massive unblock-able acid gas bomb on your target.

Costs 75 Plasma, cooldown: 26 seconds.

Acid Lance.png
Acid Lance
Start charging an acid lance that can be fired at any time on a target. Once fired, a stream of acid will launch at a point damaging anyone in it based on the amount of time charged.

Costs 50 Plasma, cooldown: 21 seconds.

Dump Acid.png
Dump Acid
Gain a speed boost and dump acidic clouds behind you. This will disable your offensive capabilities for a short time to allow you to escape.

Costs 10 Plasma, cooldown: 40 seconds.

Tail Stab
It has a two tile range dealing 1.2 times the caste's maximum melee damage, making it more useful on the bigger xenos. It takes one second of being the selected ability before it can be used.

Cooldown: 10 seconds.

Attainable Strains



Strain Abilities
Abilities: Description:
Empower PASSIVE:

  • Deploy Traps is empowered by gaining 10 stacks of Insight. These stacks are acquired by hitting Acid Shotgun pellets, at a rate of 1 for 1. Hitting a target pointblank with the acid shotgun ability will give 10 stacks of insight, as well a hitting a rooted target with Acid Shotgun immediately gives 10 stacks. These stacks cannot go beyond 10, and are consumed upon casting Empowered Deploy Traps(will have a red arrow to show that it is empowered).
  • Acid Mine is empowered by casting empowered Deploy Traps.
Deploy Trap.png
Deploy Traps
Deploys a line of temporary resin traps that, when an enemy walks over, stuns them momentarily.

Stun Time

  • Default Deploy Traps: 1.75 seconds
  • Empowered Deploy Traps: 3 seconds

Casting Empowered Deploy Traps will empower the next Acid Mine ability.

Costs 60 Plasma, cooldown: 20 seconds.

Acid Mine.png
Acid Mine
PASSIVE: Hitting an Acid Mine shaves 4 seconds off the remaining Boiler Trap cooldown per hostile living mob hit.

Designate a tile in which a 3x3 acid mine will erupt. If anyone is in the 3x3 ranged acid mine, they'll be hit with acid.

Against Hostile Mobs:

  • Default Damage: 45 Burn
  • Empowered Damage If resisted: 30 Burn
  • Empowered Damage If not resisted: 51 Burn

Against Barricades:

  • Default Damage: 76.95
  • Empowered damage: 114.075

Costs 40 Plasma, cooldown: 6 seconds.

Acid Shotgun.png
Acid Shotgun
Launch a scatter shot of small acid blobs that fire damage enemies akin to spitter/praetorian spit.

PASSIVE: Targets restrained by traps take 75% increased damage.

Default Damage(Pointblank): 91.6 Burn

Costs 60 Plasma, cooldown: 15 seconds.

Toggle Long Range Sight.png
Toggle Long Range Sight
Use "Stretch to fit" to minimize the hassle of changing icon size when zooming in/out.
Toggles long range sight in the direction you're facing.

Costs 20 plasma.

Boiler Tactics

  • Never forget your strong acid. If you ever happen upon unprotected Marine positions, notably during a Marine retreat, your acid will melt straight through everything you can get your mouth on. Sometimes, you might be asked to open up flanks through reinforced walls too.
  • Always stick with your Hive, and make sure to be the first to fallback if your sisters are getting pushed back. You are not suited for frontline combat at all and any competent tallhost will make short work of you if they manage to get into range of you. Your Acid Lance is a desperation weapon, not an alternate fighting strategy.
  • Using a strong Tier 3 caste as a shield, preferably a Crusher in most cases or a Ravager or Queen if incendiary munitions are being used, will allow you to fire despite ongoing suppression. As long range weaponry, including scoped rifles, marksman rifles and sniper rifles, are your natural counter, you will find a shield useful in large fights, as you are a priority target for people using these weapons. Defenders make excellent shields as well, and it is generally easier to get a hold of one to guard you than a T3.
  • Expect to relocate often as the fight moves forwards and backwards. Your sweet spot will always be around 8 to 14 tiles, which is your aiming range when using Enhanced Vision. Of course, if you get shot at, you need to relocate much faster, especially if you are set on fire or don't have a shield.
  • As you are stationary, you are especially vulnerable to specific weapons with a long windup, notably orbital bombardments and CAS strikes. If you hear or suspect any of those, especially if you are surrounded by sisters, immediately relocate. You cannot survive such a strike if it lands straight on you.
  • Boiler gas usually makes good points for the Aliens to push, especially if aimed at non-fortified targets. Communicating your shots might help, especially if you coordinate with another strong pushing caste like a Crusher, or even a Queen.

Boiler Stats

Tier 16
Tier 15
Tier 14
Tier 13
Tier 12
Tier 11
Tier 10
Tier 9
Tier 8
Tier 7
Tier 6
Tier 5
Tier 4
Tier 3
Tier 2
Tier 1
Health Lower Melee Upper Melee Plasma Plasma Regeneration Armor Explosive Resistance Speed Evasion

You can learn more about alien stats here.