The Hundred Herbs Sect was not known for their offensive spells and abhijnas, and the Changchun Heaven-Defying Formation lacked the intensity required to deal critical damage. However, the Mountain Defence Spell Formation became heavily fortified with the essence of heaven and earth tapped on by Hundred Herbs Grandmaster. It was definitely not penetrable by any ordinary cultivators, even if they came in large numbers.
Unless, they could strategize a battle formation, similar to the Divine Martial Army of Zhou, to merge the mana of all into a combined mana pool.
However, quantitative change may very well lead to qualitative change. When the quantity of any element increased substantially, the after effects of the change would not be proportionate and easily predicted logically anymore.
