The Covenant is a large alliance of several alien species that are more technologically advanced than Humans during the events of Halo Wars. First started as a loose non-aggression pact between the Elites and the Prophets, the Covenant quickly assimilated other races using superior firepower and tactics. The other races were given the choice of joining the Covenant or being destroyed.

Over the many years since the Covenant was founded they have taken over a large part of the Galaxy and have declared humanity a heretic race and are engaged in a Genocidal war against them.