In the Halo video-game series, the alien alliance that fights humanity is called the Covenant.
The Covenant is a theocratic empire made up of several species, including the Sangheili, Jiralhanae, Kig-Yar, Unggoy, and Yanme’e. Its leaders, the Prophets, teach that the Forerunners became divine beings and that activating the Halo rings will begin a religious journey known as the Great Journey.
This belief brings the Covenant into conflict with humanity, which it regards as an obstacle to its religion and political order. The alliance’s military forces include familiar enemies such as Elites, Brutes, Jackals, and Grunts.
The Covenant is distinct from the Banished, a later faction led by Atriox, and from the Flood, a parasitic species that threatens both sides. The Covenant’s internal political tensions become central to the story of Halo 2 and Halo 3.