The Jade Dragon Sword of the Legend of the Three Realms

There are three realms in heaven and earth: humans, demons, and beasts. After the human world was destroyed by the demon world, the beast world also became a satellite state of the demon world. Everyone became the walking dead, and Xiao Qingfeng, the crown prince of the human world, became the last person. The Beast King grew up. When he became an adult, he began to embark on the road to regaining the human world...