When the Age of Strife came to an end in the 30th Millennium, the Emperor of Mankind was determined to bring to fruition his future plans for human unity in a very hostile galaxy. He knew the time had come to unite all of humanity under one banner after the destructive birth of the Chaos God Slaanesh in the 30th Millennium reopened the galaxy to Warp travel and communication . With the use of genetically-modified warriors who presaged the development of the first Space Marines, he quickly rose to dominance on Old Earth, uniting the once-divided nations of Mankind's birthplace during the Unification Wars. He then set his sights on the wider galaxy, and with his newly-created Space Marine Legions at the forefront of his great expeditionary fleets, the Emperor launched his Great Crusade out i