A long time ago, the Millennium Earl wanted to occupy the earth, but someone used the power of God to destroy the Millennium Earl, and peace was restored to the world. But there is a fable that says: The Millennium Earl will come again... Now, in order to dominate the world again, the Millennium Earl wants to turn the dead souls into demons, but the person who can turn the dead souls into demons is actually the most important person to him. He became the "Demon", the weapon of destruction of the Millennium Earl. One day, after someone discovered a stone box, everything changed. There are some messengers chosen by God who can deal with demons. They are the "Exorcists", the nemesis of the Millennium Earl, and everything will be changed by them...