There is hidden thunder poison within that fake Heavenly Vine Flower. Yun Xiao is not lying; it's true. Moreover, the stall owner's infection by the hidden thunder poison is already very deep. It may only last for three more days before the poison enters the heart, making it impossible for even an immortal to save him.
Previously, when Yun Xiao discovered that this Heavenly Vine Flower was fake, he also found the hidden thunder poison within the fake Heavenly Vine Flower. While this kind of highly toxic substance containing thunder attribute energy is pigeon bone poison to others, to him, it is something that can enhance his thunder attribute ancestral veins.
You should know that after Yun Xiao broke through to the early stage of the Origin Seeking Realm, his second thunder attribute ancestral vein had already manifested. It was only due to an insufficient amount of thunder attribute energy that it hadn't been fully activated.
