I Actually Became a Mythical Beast in the Classic of Mountains and Seas

Xie Chengan woke up and found that he had no body and a system attached to it. The system told him that as long as he was bound to it, it would immediately give him a body, but this body was... Later, as the system rewarded more bloodlines, he gradually discovered that the bodies given by the system were all mythical beasts in the Classic of Mountains and Seas. (Note: People with a high concentration of mythical beast blood can transform into the mythical beast.)