Walker already knew that he could use natural mana to balance the chaotic mana and allow space mana to fill in areas that had grown weak due to the chaotic mana or manas being too dense and causing chaotic reactions.
However, chaotic manas could break through in to the world accidentally by themselves at times causing small pieces of corruption here and there within plants, monsters, or areas as a whole. It was somewhat a natural action even though it was easier to see it as something unnatural.
Yet, considering that all the manas outside of the elemental planes were mostly chaotic, it seemed more unnatural that the world and elemental planes were balanced.
The reason that Walker came to that gave the world such a larger space between it and the elemental plane requiring the bridges to the elemental planes to exist was simply because there was a need for that space.
