At this point in the story, we are not yet told who Divine Sabre Clan Bai TianYu's son is, so I won't give anything away. There are clues all over the place but keep in mind how much Gu Long enjoys throwing twists. We do know that Third Madame Shen is Hua BaiFeng's sister, and Hua BaiFeng was Bai TianYu's mistress. We also know that Hua BaiFeng was pregnant with Bai TianYu's child.