When a life form became powerful enough, they would be able to fuse the Spiritual Energy of Heaven and Earth into their own bodies in order to strengthen their bodies and evolve into an even higher level of life form.
The first dinosaur to fuse vital energy into its own body was a tyrannosaurus rex.
This tyrannosaurus rex was a powerful, hulking beast that was able to snap a shark-tooth dinosaur's neck with one bite. Due to its fearsome power, it was able to become a tyrannosaurus rex tribal chief en route to conquering a large territory for itself.
Soon after that, more and more dinosaurs were born with the ability to fuse vital energy into their own bodies.
Some lions, wolves, crocodiles, and other carnivorous creatures that ate the carcasses of dinosaurs with vital energy fused into their bodies also gained the ability to fuse vital energy into their bodies.
