Jingyi being Lan Qiren second it third nephew removed or in law or something So, after his parents death at Sunshot campaign.
Lan Xichen adopts him and rise that little monster with, of of course, Nie Mingjue help because they're sworn brothers and cultivation partners. And well if Mingjue is there Huisang is also going to help so Jingyi is even more a little monster now
He lost a father and don't understand how or why but he's a Lan by birth and mourning is... difficult and different . His uncle is sad and so is his other father....
But he can't help. He just hug them and try to become the best disciple so he can make his father happy and proud
Things happen, Meng Yao is dead and his father in seclusion, Nie Huisang has no heirs so... He offers Jingyi a place in Nie Qinghe, a place so Gusu Lan don't bring painful memories back while his father is in seclusion and everyone is talking about his other father...
And Jingyi accepts and travel to Qinghe because he wants to learn more about Nie Mingjue, about his father....
At this point he's a Lan yes, but he's also part Nie, with Mingjue and Xichen looking after him. So, he learns the blade and Nie sword forms. He learns about Nie curse and culture and... it's part of him now Jingyi spends half a year in Gusu and the other in Qinghe.
He.... he's confused about who he is now But, when he's father is back and go to Qinghe to find him, dressed in green and gold. When he hugs him and tell him that he's so so proud and that he looks like Mingjue and... it's to much
They're both crying now and Huisang arrive, smile hidden behind his fan and just make a last offer He doesn't have an heir, and isn't interested in having one But Jingyi is a little and brave man. He's Lan Xichen and Nie Mingjue son...
If you want, Nie Huisang says, I'll make you my heir. If you want and your father agree, Nie Qinghe will wait for you