The world of Atraria is one defined by transmigration.
For centuries, heroes have been summoned from other worlds to serve the kingdoms of Atraria against the forces of the Dark Lord, as well as the monsters he controls. If you were lucky enough to be transmigrated here, life will be pretty sweet.
Leon was not so lucky.
As a lowborn native of Atraria, he has spent much of his life working for the adventurers of the many guilds, first indirectly, and later directly. He has seen as the kingdoms became less interested in protecting the natives of the world, and more interested in acquiring more wealth and power for themselves. He knew it wasn't right, but he had no way of changing this.
This changed when he was selected as the next incarnation of the Dark Lord. After being saved by the few that still see promise in Leon, and seeing this new start as a way to set right he many wrongs of Atraria, he starts down the path to be the force that the world may not want, but desperately needs.
