User blog comment:WhiteSeraph/Alternate Timeline Idea That I'm Really Psyched About/@comment-3341288-20110927002502/@comment-25033299-20110927030436

There are a few things that fit that category

-Ever-advancing Imperial tech

-The (uneasy) alliance between sane races

-Full legions, along with the Emperor and Primarchs

-Necrons awakening rapidly on worlds taken over by the Shak'Tor.

-Tyranids coming in from the galactic north-east.