In the World of Trading, Zhang Sanfeng Is My Junior Brother

I traveled through time and became Zhang Sanfeng's senior brother, Dong Tianbao. From now on, my fate is up to me! Since you all practice martial arts, I have to cultivate immortality first! Let's have a fair deal with the idiot in the mortal world. [Trade request from Han Li: Millennium Spiritual Grass, a trade for herbs that mortals do not have. Do you accept it?