Actually chief was built up to this character by the end of halo 3 not halo 4. Halo 3 is the game where chief risks everything (including the fate of the human race) in order to save cortanna. Halo 4 in my opinion did nothing good for the story of this series. They killed one of my favorite characters [spoiler]cortanna[/spoiler]. They treated Halsey who is one of the most interesting and important characters in the series like total shit. They made the spartan program a joke. They added new aliens that where not in any way interesting. Also halo 4 mp was just terrible