Board Thread:Warhammer 40k General Discussion/@comment-27642965-20160211003725/@comment-25177957-20160609214858

So we've sort of come to that conclusion only based only on what the IoM could do in its present state in the Canon. I didn't see much mention of the Tau, Eldar, or Necrons who are of the highest tech in 40k. To be fair, plenty of scifis could take on the Imperium as it is in M41.999, but would the Halo forerunners for example, stand much of a chance against the Necrons at the height of the War in Heaven? Both would have been around at about the same time in each universe. I believe the only scifis which could take on the whole of 40k would be ones involving an active Type 5 civilization, since those can simply manipulate all existance. Type 4 civilizations would be a huge threat, but you could consider 40k's contenders at that level to be the Tyranids and the Old Ones since both of those are intergalactic forces.