Duncan's Hao 5 Theory

 Well it's a Race against the Clock

ONI want Chief Dead and the UNSC want to Chief to live so both are turned against each other and begin to hunt chief

The New Character is the hunter and The Crew of the UNSC Inifity and other Ships begin to Delay ONI bar this one hunter. So Chief begins to look for the Arbiter and The Chief teams up with his former Enemy The Didact to Stop ONI. The second concept art we got looks like Sangheilios so this could be plauseable for in the trailer we see Chief on a Forerunner world and the Machine could be the Didact's mode of transport

that is what i Have so far

let me know in the comments below what ya think

Duncannuva Dubsteping off (Wub wub wub)