From the Game's Introduction:
In a different time on a different world, it is a time of strife for the empire where the sun never sets. A thousand year old ruler precedes over an empire disrupted. Civil war erupts over the land as annexed kingdoms cry revolution. Ancient evils awake as times goes on, and evil sorcerers seek dominance of forces mysterious and unknown. In a time where the future of the empire is uncertain, there are those who take up the gun, the sword, the fist, or the mysterious art of magic, and fight.
Welcome to Jin-Shiato.