Several hundred years ago, the two worlds interacted with each other, which led to the appearance of GHOULS, who took over the world. A man stood up to destroy the ghouls and close the door that connected to the underworld and was called DATU. After five peaceful decades, the doors opened again. However, because people knew that the time would come when it would open again, they came up with a solution to turn the captured GHOULs into weapons called ESPADA.