After Shao Kahn's invasion of Earthrealm is halted by Raiden's forces of light, Raiden blasts and sends Kahn through a portal. At exactly the same time on Earth, Superman stops Darkseid's Apokoliptian invasion by blasting Darkseid with his heat vision as he enters a boom tube. These acts do not destroy either of them, but merge them into Dark Kahn, and causes the DC and Mortal Kombat universes to merge. As this happens, the characters' abilities fluctuate, causing violent "rage" outbreaks that are actually the feelings of Dark Kahn being infused in the characters from afar. With each world thinking that the other is responsible for the merger, they fight each other until only one fighter from each side remains.