World background: A crack appears in the sky, and endless monsters fly out of it. In order to fight against monsters, humans have exhausted all kinds of thermal weapons. In the realm of life and death for human civilization, someone discovered that some monsters can sign contracts with humans, and are called spiritual beasts. Humans can receive feedback simultaneously with the growth and evolution of spiritual beasts, improving their mental strength and physical fitness. It has been extended to corresponding professional beast masters and sub-professional spiritual beast cultivators. The qualifications of spirit beasts are divided into nine levels: white, red, orange, yellow, green, cyan, indigo, purple and colorful, with white being the lowest and colorful being the highest. Human qualifications are divided into four levels: A, B, C and D. A is the highest and D is the lowest.
