Xue Three used a rich broth made from precious medicinal herbs to forcefully sustain the Sword Saint's life.
Some of these herbs were picked from the Skybreak Mountain range. As the saying goes, "live off the land." Originally, in Shengle's foreign trade, demonic beasts were extremely profitable, but some precious specialties from the Skybreak Mountain range, especially rare medicinal herbs, also accounted for a significant share.
Some of these herbs Xue Three had never seen before, meaning they were unique to this world. So, he tried them himself to ascertain their properties.
In addition, many precious herbs were also collected during the southern attacks against the Qian State and the looting of the Jin State royal palace. It pained him to sell such things, so he kept them for his own use.
The 'fortifying tonic bath' Xue Three had previously prepared for his lord also contained many precious herbs.
