In which Lan Xichen, nearly thirteen, visits Nie Mingjue, newly appointed Sect Leader - and decide to swap brothers for a day.

The healers said it was trauma. Perhaps he was too young, or too sensitive; perhaps it was only that it had happened in such a way, at such an impressionable time – in any event, Lan Wangji’s reactions to his mother’s death had gone well beyond the normal signs of grief and turned into something much more severe. After some intense discussion, it was agreed that he should be temporarily sent to live as a guest in another sect to see if he would benefit from the change of scenery. From not being around the place where he was drowning in the memories of his mother. They sent him to the Jiang Sect.

Well, shit, Nie Huaisang thought, even as he comforted Jin Rusong, petting the toddler’s back to try to get him to calm down. What do I do now?

“Hey,” Lao Nie protested mildly. “Who’s the father here, me or you?” “If a-die wants a new wife, little uncle will find one that isn’t inclined to kill him.” That sounded like a recitation. “Then what’s even the point,” Lao Nie grumbled, and reached out to ruffle his son’s hair, enjoying how Nie Mingjue yelped when he did, glaring up at him with offended dignity.

Nie Huaisang’s rooms in the Unclean Realm had a little side door that no one but him ever used. Years after he’d put it out of his mind entirely, there came a terrible banging noise at that little side door, like someone was kicking at it furiously from the outside. Lan Wangji, white robes stained with blood and cheeks bright with fever, shoved something into his arms. “You have a child now,” he said through bitten lips. “Congratulations. He is called A-Yuan. I entrust you with his care, for my sect cannot be trusted with it.”

Prompt: Nie Huaisang buys Jiang Cheng a “baby on sword” (like baby on board lmao) pendant as a joke but Jiang Cheng actually uses it