The story:
Certain demons, called Shadows, have been around for centuries. They have the ability to control and turn into shadows, as the name may hint, absorb many forms of energy, and various other special abilities. In the past, rulers of many countries have hired witches and wizards to combat the dreaded shadow demons. Witches and wizards are the only known threat to the evil shadows, even in the present.
Most of the shadows have been captured, and the ones who haven't have been chased into the astral plane, where they are currently plotting their revenge.
Recently, a strong group of shadows has escaped from a research facility in the U.S.A, where the government was trying to harness their powers. The Government is calling on a group of witches and wizards to capture and/or eliminate them.
