Soul Society is a world where humans arrive after death. The Gotei Thirteen are the troops that protect the King's Domain from attacks. The Shinigami, Hollows, and Demons used to be an alliance, but someone used the new generation of Demon King, Ice Lotus, to completely destroy this relationship.
Binglian, a person with the most powerful power of the demon clan, the Demonic Eye, was attacked on her way home and her life and death are still uncertain.
The demons moved from Soul Society to reality, looking for the Ice Lotus King.