How did other sects in Yu Yan Jianghu get Wei Zi Xia Dan?

Other sects in Yu Yan Jianghu can obtain Wei Zi Xia Dan through alchemy. Wei Zixia Dan, each pill can increase the maximum qi and blood 10-20 and the maximum internal strength 1-5, with a maximum of 20 pills. Wei Zixia Dan used to be obtained only by digging treasures, but now it can be obtained by practicing Dan. Specific prescription: licorice 46, Wuling flower 2, Athena Chu 8 and Camptotheca acuminata 8.