In this site, there are certain people who recieve special spheres. The people who revieve these spheres are called a Hoseki Yaju (Jewel Beast). These people can morph into a particular animal that matches their personality. These people arent born with the animals. They are given special spheres engraved with the japanese kanji (writing) for a particular animal that matches their personality. It fuses with a certain part of their body: like their hand, neck, chest etc which allows them to morph into that animal. Each sphere is unique and although some people will have the same animal, the traits and spheres will be different.
Amongst all this, different empires and villages are building, and people want to use the power of the spheres to strengthen their military force.