User blog comment:James12708/Reapers VS. Forerunners VS. Angels from Darksiders VS. Humanity from Halo VS. Council and humanity from Mass Effect VS. Imperium of Man/@comment-1440333-20130206000208/@comment-1683193-20130207063407

Forerunner capabilties: The IoM would get stomped.
 * Capital ships are 100km long and carry double digit petaton range firepower.
 * Massive industrial capability:Built multiple Dyson spheres in a few centuries, have design seeds which can build an small battlefleet in a few hours.
 * Trillions of ships.
 * Main land vehicles are Seekers, 20 meter long assault mechs that can quickly lay waste to continents.
 * 45 1/4 meter long Forerunner UAVs can take down Covenant Destroyers.
 * FTL drives can cross tens of thousands of light years in a few hours.