The Ori are energy-based beings which live outside our universe. They are notable for being able to draw energy from those mortals who worship them.
The Ori have at their command large numbers of human worshipers to support them following a religion called Origin. These are generally kept at a roughly medieval level of technological development, though they do have access to an Industrial Base capable of assembling fleets of spacecraft. These people also serve as soldiers in the Ori's armies when the need arises.