Only monsters lived on the world of Arc Earth. That is, until the advanced civilization of humans came and colonized it for themselves. His country and his world in wreckage, Prince Evil of the Demon Kingdom fought back against the human invaders...

Setalia is a small, forested area dotted with villages in the northeastern corner of the kingdom. When word spreads that a large portal to another world has appeared, and the damage caused from it is spreading, the kingdom dispatches a lone warrior...