Zerg

The Zerg are the second creation of the Xel'Naga, after the Protoss.

History
The planet Zerus housed a small, worm-like creature, which was perfect, as the Xel'Naga were looking to give the lowest life-form "Purity of Essence", and finding the Zerg was a Godsend. They changed the Zerg from an earthworm-like creature into a parasitic worm, which supercharged the host's evolution. Wishing to avoid an earlier failure (specifically, the Protoss), they imposed a hive mind on their new creation. This "Overmind" soon turned against them, and almost completely eradicated or consumed them. The Zerg then learned of the Protoss, and decided to assimilate them, to become truly perfect. However, they needed a weapon. They settled on the Terrans, who were evolving into a close second to the Protoss.

Larvae
The Larvae is spawned from the Hatchery. The Larvae carries the gene code for every Zerg warrior. At first, the larvae can only mutate into Drones and Overlords. Each building adds more genetic information.

Egg
"Egg" is a misnomer. It is in fact a pupae. The Larvae has received a command to mutate into a strain of Zerg.

Adulthood
The mutated Larvae is now combat ready. Certain strains are for melee, ranged combat, or air support while others are soley meant to produce horrible poisons. Only the Hatchery/ Lair/ Hive and Queen carry out any reproduction. Very few Zerg have ever lived out their natural lifespans, as they are either killed in battle, or are immortal. The few exeptions are simply meant as distractions.

Varieties
There are seventeen combat sub-species of Zerg.


 * Drone, responsible for collecting Crystal and Vespane, and construction.
 * Overlord, radiates Psycic energy to controll the other Zerg with. It can be evolved into a transport class unit.
 * Zergling, Small lizard, primary warrior strain, Spawned two at a time.
 * Baneling,Mutated from the Zergling. It is a small, spherical suicide unit. (StarCraft 2 only)
 * Hydralisk, large snake-like beast, produces spines that are hurled with enough velocity to puncture battlecruiser grade armour.
 * Lurker, Mutated from the Hydralisk. It burrows and sends a row of vertical spikes into a target.
 * Mutalisk, primary air combat unit. Each shot is a disease, which spreads to two other targets.
 * Guardian, a bomber creature mutated from a Mutalisk. Can only attack ground targets.


 * Devourer, mutateded from the Mutalisk. Can only attack air targets.
 * Scourge, a small bat-like suicide air unit, spawnded two at a time.
 * Queen, a large beast that resembles a flying octopus. It is used to sow the hyper evolutionary virus, which in turn creates the Infested Terrans. It's only combat ability is spawning a pair of insects on a ground unit.
 * Broodling, a small, insect-like being that is fired from a Queen during it's egg stage. It uses the targeted organism as sperm, and it is quickly born.
 * Defiler, a scorpion-shaped crerature. It carries the gene codes of every Zerg, which it uses to produce carciogenic poisons.
 * Ultralisks, a large elephantine beast. it is clased as a seige unit, although it is a melee attacker.
 * Infested Terrans, a zombie-ish suicise bomber. it produces chemicals that are not only horribly toxic, but explosive as well.

Post Brood War experimental
These Zerg may or may not show up in SCII, and will show up in it's campaign editor
 * Nydus Worm, a long worm that erupts from the ground and drops off other units
 * Infester, a frog-like zerg that can infest terran and protoss buildings
 * Infested Marine, the evolution of infested terrans, it has a poison attack instead of it's predecessor's destructive suicide attack. It has a limited life span.
 * Lair Watcher, an evolved queen that can tunnel to another point on the battlefeild
 * Hive matriarch, an evolved Lair Watcher that can drop base defences and poison Creep to make it dangerous to traverse.
 * Corrupter, a flying squid that mind-controls other air units.
 * Overseer, an evolved overlord with detection capabilities.
 * Roach, a melee attacker with a supercharged regeneration ability.
 * Swarm Guardian, a Guardian bomber that spawns broodlings every time it attacks.

Hive Mind
The Xel'Naga were concerned that the individuality of each Zerg would cause a war. So they imposed a hive mind on their creation.

Hierarchy

 * Overmind/ Infested Kerrigan
 * Cerrebrate
 * Overlord
 * Minions