As for the "Dan infant," it rested beneath the tongue, serving also as a decoy for the Primordial Spirit that could take one's place in death. When the Primordial Spirit was lacking, it could be chewed to enhance the spirit, similar in nature to the Three Flowers, but a treasured creation of the alchemy path—an asset used in desperate situations during spells and sword fights, especially when the Primordial Spirit left the body.
This time, it was a genuine, life-and-death struggle between Xuanmen.
In fact, the contest of spells had already begun during the preparation stage with the exchange of riddles.
To deal with Xuanmen, especially an ancient one like Mountain Heng, one must be psychologically prepared for the possibility of extermination at the first slip, and then prepare to avoid detection by their calculations, before finally readying the specific instruments for spell combat.