Before the Beast Incursion, the beasts and monsters of the Beast Domain were known to constantly try and migrate deeper and deeper towards the center of the Beast Domain. This had also been true for the Mellow Manifold.
The closer the beasts and monsters drew to the center of the Beast Domain, the less space there was, the more conflict there was, and the more filtering of the weak there was.
Only the strong made it through.
Thus, stronger beasts ended up closer to the center while weaker beasts ended up further away, creating concentric layers of growing power the closer one got to the center.
"That was an intentional security purpose to protect the manifold tree, in hindsight." Rui realized. "The manifold trees and the chimeras acted with purpose. I… cannot help but strongly feel that they came here with purpose. I think this is connected with the negatron core in some way."
