Story: Following the aftermath of the Outworld invasion, Raiden is seeking to recruit new warriors to help him protect Earth from invaders. An individual dons the Ghostface outfit and goes after those recruits.

Ending: Right before killing the last victim, Ghostface takes off the mask: It is Mokap! When Raiden began looking for new warriors to assist him in protecting Earth, he did not even consider recruiting Mokap. Enraged, he sought to kill the other recruits and prove his worth as a fighter. He wore the Ghostface outfit out of personal fondness for it. Raiden, though appalled by Mokap's actions, is nonetheless impressed with his single handed slaying of other great warriors, and recruits him. It is preferable for someone this deadly to be on the heroes' side than the likes of Quan Chi's. Raiden agrees to help Mokap keep his secret by not revealing to other Earth warriors such as Johnny and Sonya what he did.

Basically, a guest character with a twist. One who turns out to be a MK character in disguise. Kobra is another character who could work for that story, but he doesn't deserve such a fine design.