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 "".
Halo: Combat Evolved
Reaching the captain's last location, Master Chief encounters a new enemy, a parasite known as the Flood. The release of the Flood prompts Halo's caretaker, the AI 343 Guilty Spark, to contact Master Chief and enlist his help in accessing the ring's Activation Index in order to use the ring's defenses. After Master Chief retrieves the Index and prepares to use it, Cortana reappears and warns him against activation. She has discovered that Halo is designed to wipe the galaxy of sentient life that the Flood use as hosts, thus starving and destroying the parasite.