The two Celestial Beasts that appeared at Dugu Wen's back were none other than the Ning Dragons.
When Duan Ling Tian was in the Genius Secret Realm located in the Jade Emperor Heaven's Nan Dou Territory, Huan'er had promised the Ning Dragons to bring them out of the Genius Secret Realm in exchange for letting them pass unimpeded into the remnant of a Realm of Gods. Eventually, the World Cleansing Divine Water managed to convince the Ning Dragons to temporarily Duan Ling Tian and promised that Duan Ling Tian would set them free when the time came.
'Their joint attacks are not inferior to the attacks of an ordinary titled Celestial Emperor. However, they could only unleash such an attack three times…' Duan Ling Tian remembered the World Cleansing Divine Water's words as though she had just said them yesterday.