Board Thread:Warhammer 40k General Discussion/@comment-50.98.233.177-20130702024407/@comment-8257990-20130704075130

To answer your question until the War in the Heavens the Immaterium was supposedly almost like a copy of Real Space, then during the War in the heavens Nurgle (and possibly Tzeentch, there is no official information on when he was "born") came about and since then the Warp just became more and more chaotic