Mu Xuanji was the sister of Granny Mu, and Mu Caisang was Granny Mu's daughter, so Mu Caisang was not wrong to call Mu Xuanji "Auntie." Over a decade ago, after Mu Caisang became a minister supporting the dragon, Mu Xuanji was in charge of teaching her all sorts of secret Poison Techniques, essentially becoming her master. However, the grand scheme of the grand purple plan was rife with conspiracies, and Mu Xuanji trained Mu Caisang not truly because of her status as a master or aunt but to use Mu Caisang to contend against Granny Mu and the Tang Sect.