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-2250460-20121114194727/@comment-3228423-20121114195240

I dunno, Legion. The Forerunners themselves are extremely powerful themselves. Bar the Flood and Mendicant's betrayal, they originally had 12 Halos that could fire independently of one another, they can just go into one system with those 40k guys, fire off a single tactical pulse, and move on to the next.