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.