Grunts are bulky humanoid creatures that share some of the physical traits of the Vortigaunt, though they are not the same species. They have multiple red eyes, large arms that end in pincers, and a smaller, gangly third arm extending from just below the chest. Grunts are also equipped with armour plating that is capable of resisting damage from certain weapons. Fire from pistols, rifles and even the tau cannon will simply ricochet off the armour.
Behaviour and Skills
Grunts are brutish creatures of tremendous strength and have been witnessed smashing through solid concrete walls. They employ military strategy and combat tactics, using cover when under fire and attacking in formation. Grunts are typically armed with a Hivehand, a living organic weapon that spawns and fires swarms of "thornets" to damage enemies. Gordon Freeman can obtain a Hivehand of his own during the course of the game.
Grunts can be found being transported through a factory on Xen, stored in pod-shaped containers. The implication is that the Grunts are manufactured beings, which is supported by the heavy amount of biological technology and weaponry featured in Xen warfare.