Just hear me out. Taking into consideration events in the past games and certain aspects of the trailer for- well its not technically Halo 5 as of now I don't think but for the sake of making it easier on me I'm gonna call it Halo 5... I've come up with a somewhat strange theory that may or may not be correct about Master Chief in Halo 5. He's either a gun-for-hire or a wanderer-typish person.

Whichever one it is something else is also likely, he's left the UNSC. For what reasons, I have no idea, possibly because he's not sure what to do now that *JUST TO MAKE SURE YOU KNOW WHAT YOUR GETTING INTO IF YOU HAVEN'T FINISHED HALO 4 YET SPOILER WARNING* Cortana is, "dead." I put quotation marks because she could easily still be alive in some way like *MASS EFFECT SPOILER WARNING DEPENDING ON YOUR CHOICES* Legion in ME3 if he died in ME2, (Just so you know he didn't die on my play through that's just what a friend of mine says so it could be a lie) you know like they transported his consciousness into another Geth's body? I'm fairly certain Cortana mentions that in Halo 4 but its been awhile and my small brain tends to only remember important events in games...

I think I might be onto something, however this could just be me speaking like a deranged lunatic so you be the judge! $PT99$