Once, every night when the realm of man went to sleep, their dreams would take them into the world of demons, where nightmares were born. One day, perhaps not so long ago, the divide disappeared. The realm of demon and the realm of man became one, and so did the demons and humans that roamed them. In this day and age, all humans are chained to a demonic attachment. The worlds seen by demons and humans have melded into something more.