Whoever keeps mentioning Covenant Engineers needs to just shut up. NOTHING about this map, save for the crashed High Charity (which doesn't even have any Covenant left on it), has anything to do with the Covenant. All of the airborne entities are Forerunner Stratosentinels (link to Halopedia would go here, but it's being all funky at the moment). How do I know this for certain? I worked with Con on designing the skybox, and I still must say, excellent job.