I'm rereading the novel, and I remember that there was a time when, here in the fandom, it was categorically stated that they were in fact father and son. I believed that for a while. Rereading the novel while reading the wiki, I discovered through updates that it was apparently false information, though it doesn't mean that they aren't father and son. So when I read a little clue in chapter 3600 I decided to make this post here, and I plan to add any other clues I find later.
Chapter 3600:
Context: After meeting again and seemingly forever saying goodbye to Qian Suyun, Li Qiye decides to leave the mountains and go to Duality Academy. This dialogue can be a small clue. Keep in mind that the author loves subtleties.
Dialogue:
"Li Qiye looked up towards the horizon and said softly: “To Duality Academy.” His eyes became slightly dazed after saying this.
The old man didn’t understand why he had this depression."
Chapter 3601:
Context: This chapter talks in detail about how amazing Duality Master is without even needing a fight. That is, all the most powerful already knew how powerful he was, but he was not famous. Perhaps because he is the only son of the Prime Emperor and the Only Empress of the Ages? The full chapter is important, but I highlight one phrase:
"The gathering of these lords was unmatched in history. Even the coronations of dao lords lacked the same extravagance and impact."
How many in all of Eight Desolates are more important than a Dao Lord? While the Duality Master's strength could be an explanation, it doesn't explain why Buddha Holy Ground didn't fight him, or why he didn't need to establish his strength through a fight. Normally in these situations, he would need to prove his strength before anything else.
Chapter 3536:
Context: I remembered this chapter from when the Four-Eyed Basilisk mentions a princess that I assume is Bu Lianxiang. I don't know why call her a princess if she is an Empress, but that's what the context shows. Li Qiye says that his son shouldn't be weak. This chapter makes it almost explicit that she had a son, and Li Qiye doesn't doubt that he is powerful. It also mentions that Li Qiye's influence remains strong in the Eight Desolates, which connects with chapter 3601 on how a powerful cultivator arrogantly enters a sect's territory, founds an academy, and instead of suffering retaliation, various powers receive them with presents. A dialogue of the chapter:
"The gathering of these lords was unmatched in history. Even the coronations of dao lords lacked the same extravagance and impact."
Dialogue:
“Princess showed up once.” The basilisk eventually brought this up.
Numerous shocking things have happened in Li Qiye’s absence but the basilisk didn’t talk about them. However, this made him put on a serious expression.
The girls became curious due to their ancestor’s appearance. Who was this princess?
“I know, sounds about right.” Li Qiye stared at the horizon; his mind drifted back into the past.
“She brought someone with her. Very few knew about this.” The basilisk added.
“A helper is necessary indeed.” Li Qiye eventually responded.
The basilisk knew that in order to be chosen, this helper was extremely capable and worthy of trust.
“Are you not worried at all, Boss?” However, he found Li Qiye’s aloof expression surprising.
“Why should I? A child can’t be a dog with a tiger for a father. Plus, there’s nothing they can’t do in Eight Desolaces.” Li Qiye chuckled.
“You’re right, Boss, I worried for nothing.” The basilisk put on a smile after realizing this. Li Qiye was right not to worry. Plus, the princess was there too. Nothing in Eight Desolaces could trouble them.
To put it bluntly, one word from her alone would summon numerous supreme masters to protect them.
Li Qiye’s prestige and supremacy as the dark crow remained in Eight Desolaces. His invisible hand was still here to grasp the world."
Chapter 3604:
Context: Li Qiye finds the Duality Master Statue with the phrase he spoke the most and shows great interest.
Dialogue:
"At the base of the statue was a famous line. However, it wasn’t the domineering one that shocked the world - 80,000 Buddhas are nothing more than statues and the gods up in the firmaments are mere floating duckweeds.
The following characters were carved - Just a mortal I am, just one thought to become cloud and mud. [2]
That’s right, this phrase is the one most often said by him instead of the line chanted during the creation of Duality Academy.
No one knew the origin of this line so it probably originated from him. Because of this, people started calling him Cloud Mud or Duality Master.
Li Qiye stared at the statue and repeated the line. This moment lasted for a while as if nothing was more interesting to him than the statue.
Yang Ling noticed this and thought that Li Qiye had a strange expression. It was hard to pinpoint it on a particular emotion."
Chapter 3605:
Context: After seeing the statue, Li Qiye is in a very rare good mood and patiently explains to Yang Lin what the phrase on the statue means. Seeing the statue, and reading the sentence made Li Qiye happy. Reading Li Qiye's own explanation, I believe that Duality Master has an amazing Dao Heart. Let's remember that Li Qiye, from the beginning of the novel, talks about how important the Dao Heart is, and although at the beginning of the novel it seemed vague, we started to understand when the concept of the four symbols of the Fate Palace appeared, and the concept of Anima was introduced. He also speaks in previous chapters that the Heavenly Dao does not exist, and that if it did, it would be Anima, or True Self, which I deduce is also the Dao Heart. That's why he sees his own Dao Heart as his most important possession, above the 13 Fate Palaces and Tetra Tribulation True Fate, and I believe that if Duality Master is really his son, he was happy in this chapter to know that his son followed the same path as him, that of cultivating the Dao Heart.
Chapter 3624:
Context: Li Qiye seems very interested in Duality Master and calls him a "legendary figure worthy of my time.
Dialogue: “Just taking a look since Duality Master is a legendary figure worthy of my time.” Li Qiye chuckled.