While the Immortal Leopard's focus on Pamela and her weapon, Corey's goal was the Celestial Dewfern.
Before appearing at the top of the ridge, he had seen the Immortal Leopard created a barrier made out of Immortal Mana, the third type of mana he had ever laid his eyes on.
Immortal Mana was the most complex and most dense mana he had ever seen- aside from the mana from Infinity Crystals- and at first, he was awed by the beauty of Immortal Mana, he was also worried that he had encountered an obstruction to his plan.
With the barrier of Immortal Mana protecting the Celestial Dewfern, neither Kiefer, Selene, Willow, or even Rhea would be able to destroy it and uproot the herb while they were battling the Immortal Leopard.