The Zerg are composed of several different types of creatures that have been integrated into the Swarm by the Overmind. These creatures, or breeds, have been selectively evolved to become efficient killers and to assist the Zerg in their quest for ultimate power. The Zerg do not utilize technology in the common sense, but their natural weaponry and armor is comparable to the most advanced gadgetry employed by any other species. This biological evolution, combined with an unmatched savagery and their blind devotion to the Overmind, make the Zerg an extremely formidable and deadly foe.

The Zerg have been found in all types of environments, including deep space. They have adapted themselves to the rigors of space travel, although it is not exactly understood how they are able to do so. The center of a Zerg habitation is the Hatchery. Their nests are composed of a thick organic matter, nicknamed the Creep, which provides nourishment for the Zerg and provides organic mass for Zerg Larvae and Drones to facilitate their transformation into larger forms. The Creep expands and covers the area around the Zerg hive, and is very difficult to eradicate.

Note: All information in Red text pertains only to StarCraft: Brood War.