In StarCraft II, the Zerg use larva to produce most of their combat units.
Zerg production is centered on larva, which emerge from Hatcheries, Lairs, and Hives. A player morphs each larva into a worker, combat unit, or specialized creature. This system lets the Zerg rapidly change production priorities, but every larva used for an army unit is also a larva that cannot become a Drone.
Terran players train units from structures such as Barracks and Factories. Protoss players warp units through structures such as Gateways. The Xel'Naga are an ancient species in StarCraft lore, not one of the three playable races in standard multiplayer.
Zerg buildings are also created by Drones, which transform into the structure and are consumed in the process. Creep supports Zerg infrastructure and movement, reinforcing the faction's distinctive biological economy and making Zerg production fundamentally different from the other races.