The Covenant are a sprawling empire of united races of aliens. They believe in The Great Journey, where they use the Halo rings to become gods. Their weapons revolve around Plasma. They use the Energy Sword, Plasma Pistol, Plasma Rifle, Spiker, Mauler, Plasma Repeater, Needler, Gravity Cannon, Focus Rilfe, and Needle Rifles.
The Sangheili are known as Elites. They are strong, and serve as the San Shyuum's body guards, yet their only classification of guard is the Sangheili Honor Guard.
The Kig-Yar are mercenaries, hired to save their race from destruction by the Covenant. They play the role of snipers and cannon fodder.
The weakest and most low ranking of the Covenant. They serve the roles of support and cannon fodder.
They are orange foot-long worms that build into colonies known as MgaelLekgolo, or Hunters. They play heavy support and anti vehicle roles in colonies, and Forerunner tech finders not in colonies.
Ape-like aliens, the Jiralhnae, or Brutes, are uncivilized. They usually play infantry and leader roles, commanding Unggoy and Kig-Yar.