It's fate

 Medicine Pavilion in the rain mountain, the most important place is the pharmacopeia court.

 In this pharmacopeia court, there are more than 80% of Dan formula in the entire Yunshui World, which has been accumulated by the Medicine Pavilion for ten thousand years.

 There are even a lot of Dan formula, which did not belong to the Yunshui world. In this Pharmacopoeia, there are also collections.

 In the entire Medicine Pavilion, only the owner can enter the Pharmacopoeia Pavilion at will. Anyone who has no permission from the owner can not enter the Pharmacy Court.

 If they enter rashly, they will either be expelled from the mountain gate or be abolished and become ordinary people.

 The Pharmacopoeia Pavilion was originally used to store thousands of Danfangs. However, one day before a hundred years ago, the owner of the Medicine Pavilion, Ouyang Changyi entered the Pharmacopeia Court and did not appear for three years.