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-50.80.96.33-20130124001031/@comment-4967682-20130124010028

From Paragon Lost, there were maybe a few hundred Collector Cruisers. Significant to the UNSC, Covenant, or any ME race... but not the Forerunners. Like I said: that Forerunner battleship at the end of Halo 4? It took a SMAC round and kept going. It had to be taken down by internal sabotage. And a single SMAC round carries more firepower than an entire Reaper fleet. If a single Forerunner ship can take over 50 gigatons of firepower and not even be slowed down, then nothing the Reapers can do will scratch them (except RKVs, but those have their own sets of problems, see my comments on that below).