So does this mean what he's fighting isn't the will of the world?
Instead is it
A: The will of humanity/good and likewise he himself is the will of demons/evil
or
B: The will of the world has divided stuff, the great spirits only protect the world, the humans(heros) protect peace, and the demons bring evil.
And
The will of the world did so in this way to avoid the real evil from arising (the mc's power), considering the past demon lords wanted destruction of the world but the great spirit never acted against them since she knew they couldn't do so.