[quote]Sweet, now reading this I have two last question. Who is agent Locke, and what makes him so important in the Halo 5 trailer. And Who/what are the Promethians?[/quote]Agent Locke is an ONI agent who specializes in target tracking and capturing/eliminating. His latest mission is to track down the Master Chief. Whether it's to capture or kill, we don't know yet, but the trailer gives us a pretty good indication. The Prometheans are an elite sect of the Forerunner Warrior-Servants. Towards the end of the Forerunner-Flood War, the Prometheans agreed to be composed by the Didact in order to combat the Flood without the threat of biological infection. While effective, it wasn't enough, which lead the Didact to conscript the majority of humanity into his Promethean ranks