In a world called the Spirit Realm, humans coexist with various spirit beasts. Through a mysterious power called the "Beast Control Contract", humans can establish a deep connection with the spirit beasts, fight and grow together. The spiritual realm is divided into five major realms, each realm has its own unique species and culture of spirit beasts, and in the center is the legendary holy land of spirit beasts - the Abyss of Beasts, which is the holy land that all beast masters dream of.
