The Covenant, led by their religious leaders called the Prophets, worship an ancient civilization known as the Forerunners, who perished while defeating the parasitic Flood. The original trilogy centers on an interstellar war between humanity and an alliance of aliens known as The Covenant. The central focus of the franchise builds on the experiences of Master Chief John-117, one of a group of supersoldiers code-named Spartans, and his artificial intelligence (AI) companion, Cortana. The franchise is currently managed and developed by 343 Industries, and owned and published by Xbox Game Studios. Halo is an American military science fiction media franchise created by Bungie.