So in the MCC trailer the ending section with Agent Locke (and who some have presumed to be the Arbiter) it is clear Locke is trying to find Chief. Why?
Some have anticipated that the two will team up, and defeat the flood together. I have my own proposition which I find far more likely, albeit only based upon one true fact: Agent Locke is an assassin working under ONI Section 3.
Which brings me back to the question, what is his place in canon? I suspect he is sent to assassinate the Chief and tie up several loose ends for the ONI. Also assuming Chief has gone rogue and is seeking out the Ark or Mendicant Bias it’s no question that ONI would catch wind of it at some point and want to beat him to it, and probably get rid of Chief.
These are just some thoughts I had. Discuss.