C574
The reason why Xiao Tian allowed Tang Xuejian to follow him to Divine Realm was mainly to let Tang Xuejian see Goddess Xi Yao. As for Xu Changqing, it was purely a side effect.
He also wanted to see if he could find a way to make Xu Changqing live for good within the Divine Realm.
After all, Zi Xuan was his disciple now. As his master, he had to contribute to his disciple's happiness