Short version: The hero follows the evil king's brother, who becomes a mist. He gets sucked to a world with the people who had had the plague. He meets an old man who tells him that place is where evil versions of people live, and the plague causes them to swap positions with the people of the above world. The hero finds his evil clone at the shrine of order and chaos trying to escape to the above world. He breaks the shrine, causing order to flow into the hero's sword, and chaos sucks in the evil hero's essence into the sword, creating the sword of plague. After defeating the sword of plague, all the people who have been infected returned to the above world and thanked the hero. However, a remnant of Chaos disappeared into a black portal.
Note: I would prefer to be a scriptwriter than artist.
