Well, it might be that the dragon has a connection to a long-lost magical realm or maybe it holds the key to solving a major problem in the story. That's all up to the imagination of the fanfic author!
The secret could be something unique to the fanfiction's creative take, like the dragon having a special power or a hidden origin.
The secret could be anything from the dragon being able to communicate with other mythical creatures to having a hidden ability that only reveals itself in times of great danger. It really depends on how the fanfiction writer wants to spin the tale.
If you want the clearest chapter reference, go to Chapter 79. Early on, Jiang Li leisurely said, "I bought this weeding machine, and according to...; later, the chapter leans on He, himself, had just finished weeding a piece of land, and to top it off,....
If you want the clearest chapter reference, go to Chapter 13. Early on, Sensing that something was off with Jiang Yan, Jiang Yan dismissed the...; later, the chapter leans on What on earth do you mean?" Ignoring him once again, Jiang Li shifted her....
The best chapter pointer here is Chapter 26, "Sending My Big Brother to a Transformation Variety Show". It opens with Shen Lan was bent over processing a large stack of press briefs on her... and closes on If you think you can use our family connection to have me handle this....
Chapter 936, "When Did the River Moon First Shine on People [Extra: River Moon Chapter]", is the clearest early answer because it turns University's situation into a concrete plot event.
Look to Chapter 72 for the clearest answer. It begins with Jiang Yan was still griping when suddenly a fair hand reached out beside..., keeps building through I'll take these, thank you." In an instant, five pairs of eyes stared over..., and lands on Think about it." Jiang Yan fell silent..
Chapter 15 is the strongest chapter-level answer because it starts from Jiang Shixu woke up from those nightmares filled with blood and darkness,... and follows through on Since she didn't move, Jiang Shixu also stayed put, and the kitchen, which....
A practical answer is Chapter 16, because it turns the idea into a concrete scene. The chapter opens with Just as the words fell, Jiang Shixu swiftly cast his eyes downward., adds pressure through Smelling the pleasant jasmine scent coming from her, his tense nerves..., and ends on Jiang Shixu.
The best chapter pointer here is Chapter 54, "Acting Righteously Hits the Trending List Again!". It opens with Five minutes later, the people of Chixia Village, who had received the... and closes on She was also polite and friendly, and to top it off, she was good-looking,....
If you want the clearest chapter reference, go to Chapter 19. Early on, What criminal law is this or that, this was originally none of your...; later, the chapter leans on In high school, she got into the international class by throwing money....
The best chapter pointer here is Chapter 15, "The Autistic Teen Jiang Shixu". It opens with Jiang Shixu woke up from those nightmares filled with blood and darkness,... and closes on Since she didn't move, Jiang Shixu also stayed put, and the kitchen, which....