Every single native in Central Plains gradually adapted to Darlac as their body sizes morphed accordingly. Monsters from a cultivation world were too massive as compared to one from a magic world at similar power scales.
In the Darble World, all creatures were tiny in comparison. And now, the various races in Central Plains were simply shrinking in response. But, there was one advantage to the large monsters here.
When their bodies shrunk, the excess body mass was burned into energy and converted into their reservoir of Darlac. So, they ended up profiting in that way, gaining a leap in strength in the new rules of the world they lived in.
708 Grade 2 Systems!
