There's something so deeply bittersweet and aching about Wangxian and their little one.
This tiny innocent born into war, plucked from horror into a barren wilderness, planted among radishes and nourished with affection.
Wei Wuxian is such a natural parent, so silly and so caring and so protective. And he and Lan Wangji are so enchanted by watching each other play with and care for this child, who lights up at teasing and delights over simple gifts and is so full of pure and easy love.
And then there is blood and fire and death and fever.
And this child that might have been in some ways theirs, some remnant thing that binds Lan Wangji to a memory, does not remember.
Lan Wangji loves him for his own sake, of course, more as time goes on; as agony fades to a dull constant ache and Sizhui develops ever more into his own person. He is a constant source of pride and joy and parental concern and motivation for Lan Wangji to grow up in ways that he had not before.
And in the end, Wei Wuxian comes back and Sizhui remembers and they are finally a family...but it does not erase the things that were missed. And sometimes Wei Wuxian looks at little drawings Sizhui made as a child, or toys he played with, and tears up a little over having not been there. Sometimes Lan Wangji thinks of a particularly scary illness or a challenging school situation and imagines what it would have been like to have a partner to parent with all along.
There is a happy ending...but it does not return what was lost.
And yet...Sizhui comes to them blushing to talk about a crush. He brings his confusing homework to them. He seeks their advice before night hunts. They get to be parents together. One night, when Sizhui has been injured - not severely but enough to be worrying, enough to run a mild fever - Lan Zhan and Wei Ying sleep on either side of him, watching over him. Their eyes meet over the head of their precious child, and in that moment it as if there were no years where they did not do this together.
What was lost cannot be returned...but there is a happy ending.
