The Grade of Mana Flow
Humans are not born equal, whether it's based on their more well-off parents or perhaps their better-off siblings. Even the environment in which they live affects how their future will be. Because that's actually human life has been determined from the beginning since they were born into the world.
Of course, humans can fight their fate. Struggling with all his might to spend hour after hour to change the direction of the wheel of destiny. Maybe they will succeed, maybe they will fail and lie with the corpses of other warriors. But at least this life still gives humans the opportunity to choose their own path.
However, there is one thing that humans cannot change.
Genetics.
No matter how hard they tried, humans would not be able to change their genetics. Even using magic technology is still impossible. Genetics is like a limiting bond of the human imagination itself.