Daisuke Niwa is an ordinary, if slightly unlucky, middle school student. On his fourteenth birthday, he comes down with a 'condition' that has plagued the men in his family for three hundred years. When he sees his crush, Risa, he transforms into his alter ego, the phantom thief Dark. Unfortunately, when Dark sees his crush, Risa's twin Riku, he transforms back into Daisuke. The only cure for this craziness is if Daisuke can get Risa to fall in love with him and Dark can get Riku to fall in love with him. But that's going to be a problem, seeing that Riku hates Dark and Risa loves him.
Talented Engineering Professor Wi Geonwoo' was fired from the research center he worked at all his life and was kidnapped by a mystifying light, only to be dropped into a mysterious world. Engineering Professor Wi Geonwoo was approached by an entity that called himself "A God With No Face" and was forcibly given a blue stigma. In this new world, individuals with blue stigmas are hunted, while the ones with red or crimson stigmas are considered the hunters who seek out their prey. Will Wi Geonwoo' with his blue stigma, be able to survive as one of the hunted? "I will be your strength, so lend me your body." To make matters worse, Ash Glaive," a strange slime-like individual appeared. Together with Archmage Ash, and the imagination and monster-like bodies of the engineers, they start the war against the red stigmas.