Halo is a science fiction vieo game series, created by Bungie Studios and published by Microsoft Game Studios. It centers on the Master Chief, a cybernetically-enhanced human super-soldier, equipped with technologically-advanced battle armor and an artificial intelligence (AI) companion, Cortana. He aids the humans of a futuristic universe battle the Covenant, a theocratic alliance of alien races. In this science fiction setting, the term "Halo" refers to Halo megastructures, large, habitable ringed structures, similar to Larry Niven's ringworlds.