"Last, but not least, is the spawner of the swarm: the Swarm Host. These guys can create numerous pesky locusts and now, we know how. So check out all the details, and arm yourself and those around you with an understanding of one of our greatest foes."

A swarm host

The swarm host (otherwise known as the "egg monster" by terrans)[1] is a zerg strain in StarCraft II: Heart of the Swarm.

Overview[edit | edit source]

"Adapted using primal essence. Spawns locusts to kill enemies."

A swarm host spawning locusts

Generated by the infestation pit, the swarm host burrows into the ground in order to provide a seemingly endless supply of locusts.[2] A single swarm host is capable of overwhelming an entire army.[3] The large, mushroom-shaped structure on the swarm host's back is a breeding ground that weaponizes the millions of diminute larvae inhabiting the creature's acidic bloodstream. Through a simple system of membranes for matter exchange, glands that pump the offspring full of hormones to hyper-accelerate growth, and ducts for efficient transportation to the bubbling pockets on the surface of the incubator, the swarm host births deadly, short-lived locusts to destroy threats to the Swarm. The larvae also feed on damaged tissue, sealing wounds, and destroying anything foreign that enters their domain. When the creature is threatened or engaged in combat, a subtle chemical reaction signals the larva to head for the incubator, where they are evolved into living weapons.[4]

A swarm host

The swarm host is often used in defensive maneuvers.[2] Its legs boast powerful muscles that allow them to vibrate at hypersonic speeds, not unlike the teeth of the nydus worm. Despite that, the creature couldn't burrow fast enough to adapt to shifting battlefield conditions. To correct this, a set of fragile (albeit regenerating) capillaries was put into place. Now, when the swarm host digs, the capillaries break and the creature's acid blood softens the soil, allowing it to go underground in seconds. Flexible osseous structures of varying thickness slide and lock into position when the swarm host prepares to strike. Bearing a resemblance to siege tank hydraulics, this specialized skeletal system allows the swarm host to maintain position and balance when spewing locusts or when under heavy fire.[4] The swarm host lacks mobility however, which leaves it vulnerable to quicker enemies with area damage like the hellion.[2]

A Leviathan Brood swarm host

The swarm hosts of the Leviathan Brood are uniquely specialized for amphibious assault and bear many genetic advantages that allow them to quickly move through the oceans and assail their prey.[3]

History[edit | edit source]

Projenitors of the swarm hosts, named primal hosts, were first encountered by the Swarm utilized by the primal zerg on Zerus, used against Kerrigan's forces by the pack leader Brakk.[5] Swarm host strains were incorporated into Kerrigan's Swarm soon afterwards by Abathur, adapted through primal essence.[6] The essences of the primal host were later adapted in to create the swarm host.[3]

Reports within the Terran Dominion have suggested that swarm hosts have developed the ability to spawn locusts without being burrowed.[1]

As primal zerg fought alongside the Zerg Swarm, many swarm hosts strains began to merge with their primal host progenitors, creating strains with many similar traits between the two.

Swarm hosts enslaved by the Cerberus Program were enhanced with microfactories that allowed them to control locusts spawned from them with remote controlled head gear.[3]

During the End War, a number of swarm hosts came under Amon's control, and were inducted into his brood. They were destroyed by Tal'darim Highlord Alarak and Nerazim Matriarch Vorazun on Aiur.[7]

Game Unit[edit | edit source]

StarCraft II[edit | edit source]

Swarm hosts cannot attack directly, and summon locusts to fight for them. A swarm host can summon two locusts at a time.

Versus[edit | edit source]

As of Legacy of the Void, swarm hosts can produce locusts on the move;[8] this ability is now manually activated.[9] These locusts are more powerful but do not spawn as quickly. In the late game the locusts can fly[8] over terrain. The locusts must then "swoop" to attack.[9]

Swarm hosts require the burrow ability to be researched for them. They no longer collide with locusts.[10]

Swarm hosts require detection to locate, but reward positioning. Air units and flanking attacks are helpful against groups of swarm hosts, but leaving them unattended and attacking waves of locusts can slowly wear down an army.

Upgrades and Abilities

Many zerg ground units may burrow, becoming invisible and revealed primarily by detectors, and may not move or attack while burrowed.

Exceptions include:

  • Roach, which may move while burrowed
  • Lurker, which may attack while burrowed
  • Infestor, which may move while burrowed
  • Baneling, which can detonate while burrowed.

Some units can unburrow via autocast, causing them to emerge and attack when an enemy moves into range.

The ability is not smartcast.

Usage
Hotkey R
Cost 2 seconds to burrow, 1 second to unburrow seconds
Acquisition
Purchased from Hatchery/Lair/Hive
Hotkey B
Cost 100 Minerals 100 Vespene gas 71seconds
Required Lair (WoL)
Hatchery (HotS/LotV)
ve
FlyingLocustIcon.png
Flying Locusts

Allows locusts spawned by swarm hosts to fly. Flying locusts can use Swoop to land and attack units.

Automatically available in Legacy of the Void.

Acquisition
Purchased from

Infestation pit (HotS)

Already researched (LotV)
Hotkey L
Cost 200 Minerals 200 Vespene gas 160seconds
ve
  • +1 bonus to armor per level for zerg ground units.
Acquisition
Purchased from Evolution chamber
Hotkey C
Level 1
Cost 150 Minerals 150 Vespene gas 114seconds
Level 2
Cost 225 Minerals 225 Vespene gas 136seconds
Required Lair
Level 3
Cost 300 Minerals 300 Vespene gas 157seconds
Required Hive
ve

Heart of the Swarm[edit | edit source]

Swarm hosts appear as primal zerg enemy units in "Waking the Ancient."[5] Afterwards, the player gains access to them in "The Crucible."[6] They have access to a number of upgrades in the evolution pit.[11]

In the Heart of the Swarm campaign, swarm hosts function differently. They do not burrow, instead using the root command. While rooted, a swarm host cannot move but is still visible. They do not autocast spawn locusts in the same way as in the multiplayer game. Instead, they only spawn locusts while rooted when an enemy comes into range, or the player selects spawn locusts and clicks a location.

Upgrades and Abilities

The swarm host upgrade screen

SC2ZergBurrow.jpg
Burrow

Allows swarm host to burrow. Can still spawn locusts while burrowed.

Primal sequences of swarm host resistant to improvement. Frustrating. Simple adaptations become incredible challenge. Essence constantly adapting, rejecting mutations. Aggravating. Difficult, but can enable burrow. Locust spawning will remain functional while submerged.

Campaign Acquisition
ve
SC2 RapidIncubation Icon.jpg
Rapid Incubation

Locusts spawn 20% faster.

Locust production inefficient. Will greatly benefit from redundancy removal. Sequences are complex, wasteful. Byproduct of wild, uncontrolled evolution. Simplification of sequences will allow swarm hosts to incubate full-grown locusts at rapid speeds.

Campaign Acquisition
ve
SC2 PressurizedGlands Icon.jpg
Pressurized Glands

Locusts can attack both ground and air units.

Swarm host defense reliant on locust organism. Locust secrets solvent fluids, projectiles towards enemy. Can mutate glands, increase pressure. Will allow projectile to reach incredible height. Attack both ground and aerial targets.

Campaign Acquisition
ve

Co-op Missions[edit | edit source]

Abathur is able to mutate swarm hosts in Co-op Missions. Like other variants, they spawn 2 Locusts to attack, which deal a total of 16 DPS in co-op. The Swarm Host itself comes with Burrow already unlocked, and can be upgraded when Abathur reaches Level 9 with the Deep Tunnel ability so they can move around the map faster. They spawn locusts much more quickly with biomass.

Instead of this unit, Dehaka is able to create the primal host variant, as well as its primal evolution the creeper host.

Upgrades and Abilities
SC2ZergBurrow.jpg
Burrow

Buries the unit underground. Burrowed unit are unable to move or attack, but they cannot be seen without detection.

Usage
Hotkey R
Cost 2 (burrow)seconds
1 (unburrow) seconds
Campaign Acquisition
Unlock Initially available.
ve
SpawnLocustIcon.jpg
Spawn Locust

Spawns 2 locusts with timed life at target point. Can be set to autocast.

Usage
Hotkey C
Duration 25 seconds
Cooldown 15 seconds
ve
SC2 Abathur AC - Biomass.png
Biomass Gatherer

Swarm hosts gain +3% hit points and +0.5% Spawn Locust cooldown per stack of Biomass. Can stack up to 100 Biomass.
Passive: Heal 1% hit points per Biomass.

Essence Hoarder: Swarm hosts can collect an additional 25 Biomass (summary 125).

The Limitless: Swarm hosts can collect an additional 100 Biomass (summary 200), but gain +1.5% hit points and +0.25% Spawn Locust cooldown per stack of Biomass.

Usage
Range 4
Notes

The amount of collected biomass vary, based on difficulty and the amount of supply consumed by the killed enemy unit:
Collect 5 biomass per supply (Casual and Normal)
Collect 4 biomass per supply (Hard)
Collect 2.5 biomass per supply (Brutal)

Campaign Acquisition
Unlock Initially available.
Acquisition
Basic
Effect Hit Points: +3.6 per Biomass. Up to a maximum 480
Spawn Locust cooldown: -0.075seconds per Biomass. Down to a minimum 7.5seconds
With Essence Hoarder
Effect Hit Points: +3.6 per Biomass. Up to a maximum 570
Spawn Locust cooldown: -0.075seconds per Biomass. Down to a minimum 5.625seconds
With The Limitless
Effect Hit Points: +1.8 per Biomass. Up to a maximum 480
Spawn Locust cooldown: -0.0375seconds per Biomass. Down to a minimum 7.5seconds
ve
Icon Zerg Brutalisk.jpg
Evolve to Brutalisk

The Swarm host evolves into a Brutalisk. Can be set to autocast.

Essence Hoarder: Evolve to Brutalisk is unavailable.

The Limitless: Evolve to Brutalisk is no longer limited to 3, but requires 200 stacks of Biomass.

Campaign Acquisition
Unlock Reach Abathur Level 2.
Acquisition
Basic
Cost -1 Control 5seconds
Required Collect 100 Biomass
Cannot have more than 3 at the same time.
With The Limitless
Cost -1 Control 5seconds
Required Collect 200 Biomass
ve
SC2 Abathur AC - BiomassRecovery.png
Biomass Recovery

When killed, your units have a 50% chance to drop all their Biomass.

Essence Hoarder: Increases the Biomass Recovery chance from 50% to 100%.

Campaign Acquisition
Unlock Reach Abathur level 7.
ve
DeepTunnel SC2 Icon1.jpg
Deep Tunnel

Swarm hosts quickly burrow to a targeted visible location.

Tunneling Horror: The Deep Tunnel no longer requires vision.

Usage
Hotkey D
Cost 2 seconds
Cooldown 30 seconds
Campaign Acquisition
Unlock Reach Abathur Level 9.
Acquisition
Purchased from Infestation pit
Hotkey D
Cost 200 Minerals

200 Vespene gas
120seconds

Mastery: -2.4seconds per Structure Morph and Evolution Rate mastery point. Down to a minimum 48seconds
Required Hive
None (with Tunneling Horror)
ve
SC2 PressurizedGlands Icon.jpg
Pressurized Glands

Locusts can attack both air and ground units.

Campaign Acquisition
Unlock Initially available
Acquisition
Purchased from Infestation pit
Hotkey P
Cost 200 Minerals
200 Vespene gas

120seconds

Mastery: -2.4seconds per Structure Morph and Evolution Rate mastery point. Down to a minimum 48seconds
Required Hive
ve
SC2 ZergGrndCara.gif
Zerg Ground Carapace

Increases the armor of zerg ground units.

Usage
Passive
Campaign Acquisition
Unlock Initially available.
Acquisition
Purchased from Evolution chamber
Hotkey M
Level 1
Cost 100 Minerals

100 Vespene gas
160seconds

Mastery: -3.2seconds per Structure Morph and Evolution Rate mastery point. Down to a minimum 64seconds
Effect Armor: 2
Level 2
Cost 175 Minerals

175 Vespene gas
190seconds

Mastery: -3.8seconds per Structure Morph and Evolution Rate mastery point. Down to a minimum 76seconds
Required Lair/Hive
Effect Armor: 3
Level 3
Cost 250 Minerals

250 Vespene gas
220seconds

Mastery: -4.4seconds per Structure Morph and Evolution Rate mastery point. Down to a minimum 88seconds
Required Hive
Effect Armor: 4
ve

Development[edit | edit source]

The following section contains information from a previous version of StarCraft II which is no longer valid.

Infestor development image, dubbed "swarm host"

Main article: Infestor/Development

The swarm host[12] was expected to be available in the campaign and map editor of StarCraft II.[13] During Heart of the Swarm, the design was revisited, but it was initially of a flying unit much like a overlord with the ability to land, burrow, and produce "swarmings." This was scaled back to a ground based unit.[14] The idea behind its current design was to give zerg players their own siege unit, but make sure it functioned in a different manner to the siege tank or colossus.[15]

The swarm host's current form was to give the zerg a new aesthetic, something to distinguish the unit from the usual claws and teeth that other zerg units possess.[16]

"Egg monster" and "digester" are terms used for the swarm host in the beta files of Heart of the Swarm.[17]

In the Heart of the Swarm campaign, the swarm host had two unused upgrades. One increased the movement speed of locusts by 50%, the other increased their attack speed by 20%.[18]

Balance Update #8 of the Heart of the Swarm beta increased the swarm host's health from 120 to 160.

The swarm host changed dramatically in April 2015 for patch 2.1.9. Their cost was changed from 200 minerals and 100 gas to 100 minerals and 200 gas, their supply was increased from 3 to 4, and their movement speed increased from 2.25 to 2.95. The Summon Locust ability is now manually cast with the hotkey "C", and the cooldown is increased from 25 seconds to 60. It can be used whether the swarm host is burrowed or not, which now must be researched. The Enduring Locusts upgrade was replaced with Flying Locusts, and locusts no longer collide with swam hosts.[19]

For Legacy of the Void, patch 2.5.1 Balance Update #1 reverted the unit and supply costs to 200/100 and 3 supply, and removed the Flying Locusts upgrade. Swarm hosts could also move while burrowed, though this was reverted in the next patch. Patch 3.3 reduced the unit cost to 150/100, and 3.8 to 100/75.

Swarm hosts' move speed was reduced from 4.13 to 3.15 in patch 4.0, in order to increase the number of counter-play options against them.[20]

EnduringLocusts SC2-HotS Icon.jpg
Enduring Locusts

Increases the lifespan of locusts by 10 seconds (to 25 seconds). This upgrade was removed from HotS in the April 2015 update, as the locust's base lifespan was increased to 25 seconds. [21]

This upgrade is not present in Legacy of the Void.[22]

Acquisition
Purchased from Infestation pit
Hotkey L
Cost 200 Minerals 200 Vespene gas 120seconds
ve

Heroes of the Storm[edit | edit source]

Heroes DevLog2.jpg

The following section contains information from Heroes of the Storm and is not canon to StarCraft continuity

Swarm hosts appear as a boss mercenary on the Warhead Junction map of Heroes of the Storm.[23]

Variant Strains[edit | edit source]

Images[edit | edit source]

Skins
Portraits

References[edit | edit source]

  1. 1.0 1.1 2015-09-18, NYCC 2015 – James Waugh’s StarCraft Field Manual Signing Schedule. Blizzplanet, accessed on 2015-09-23
  2. 2.0 2.1 2.2 Swarm Host, Blizzard Entertainment. Accessed on 2014-01-08
  3. 3.0 3.1 3.2 3.3 Blizzard Entertainment. StarCraft II: Legacy of the Void. Collections Tab: Skins. July 19, 2017 Cite error: Invalid <ref> tag; name "Collections" defined multiple times with different content
  4. 4.0 4.1 2014-12-04, Swarm Host Science. Blizzard Entertainment, accessed on 2014-12-06
  5. 5.0 5.1 Blizzard Entertainment. StarCraft II: Heart of the Swarm. (Activision Blizzard). PC. Mission: Heart of the Swarm, Waking the Ancient (in English). 2013-03-12.
  6. 6.0 6.1 Blizzard Entertainment. StarCraft II: Heart of the Swarm. (Activision Blizzard). PC. Mission: Heart of the Swarm, The Crucible (in English). 2013-03-12.
  7. Blizzard Entertainment. StarCraft II: Legacy of the Void. Mission: Templar's Return. (in English). November 10, 2015
  8. 8.0 8.1 Blizzard Entertainment. 2014-11-07. Legacy of the Void - Multiplayer Update: Zerg. Blizzard Entertainment. Accessed 2014-11-09.
  9. 9.0 9.1 Blizzard Entertainment. 2014-11-08. Legacy of the Void: Multiplayer Preview. Blizzard Entertainment. Accessed 2014-11-09.
  10. Cite error: Invalid <ref> tag; no text was provided for refs named BetaPatch
  11. Blizzard Entertainment. StarCraft II: Heart of the Swarm. (Activision Blizzard). PC. Evolution pit units (in English). 2013.
  12. 2010-02-28, StarCraft II Beta Game Images. StarCraft Legacy. Accessed on 2010-06-22
  13. Didier, Samwise, PC Gamer staff. "Alien Makeover: Blizzard shows off the new look of the zerg." PC Gamer June 2009: 20-22.
  14. PhilGonzo Deviantart. Zerg Swarm Host Devinaart.com. April 20, 2019
  15. June, 2012, Starcraft 2: Heart of the Swarm "New Units" Explained by David Kim. G4, accessed on 2012-06-21
  16. June, 2012, Starcraft 2: Heart of the Swarm "New Units" Gameplay Preview With Sam Didier. G4, accessed on 2012-06-21
  17. Blizzard Entertainment. Heart of the Swarm beta Map Editor. (Activision Blizzard) (in English). September 4, 2012
  18. Blizzard Entertainment. StarCraft II: Heart of the Swarm Map Editor. (Activision Blizzard) (in English). March 12, 2013
  19. Blizzard Entertainment. 2015-04-07. Heart of the Swarm Balance Update -- April 9, 2015. Blizzard Entertainment. Accessed 2015-05-11.
  20. 2017-08-17, StarCraft II Multiplayer - Major Design Changes. Blizzard Entertainment, accessed on 2017-08-20
  21. Blizzard Entertainment. 2015-04-07. Heart of the Swarm Balance Update -- April 9, 2015. Blizzard Entertainment. Accessed 2015-05-11.
  22. 2015-03-31, StarCraft II Legacy of the Void Beta Release Patch Notes. Blizzard Entertainment, accessed on 2015-04-03
  23. Blizzard Entertainment. Heroes of the Storm (Blizzard Entertainment) (in English). June 2, 2015
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