Master Chief (Halo)
MCPON John-117, or "Master Chief", is a fictional character and the protagonist of the "Halo" fictional universe created by Bungie. Master Chief is a playable character in the series of science fiction first-person shooter video games "", "Halo 2", "Halo 3", "Halo 4", and "". Outside video games, the character appears in books and graphic novels—"", "", "", and ""—and has cameos in other "Halo" media, including "", "", "The Halo Graphic Novel", "Halo Legends" and "".
Cortana (Halo)
Cortana is a fictional artificial intelligence character in the "Halo" video game series. Voiced by Jen Taylor, she appears in "" and its sequels, "Halo 2", "Halo 3", "Halo 4", and "". She also briefly appears in the prequel "", as well as in several of the franchise's novels, comics, and merchandise. During gameplay, Cortana provides backstory and tactical information to the player, who often assumes the role of Master Chief Petty Officer John-117. In the story, she is instrumental in preventing the activation of the Halo installations, which would have destroyed all sentient life in the galaxy.