Alright so. I had a plan when I started this thing, I swear, but something went wrong along the way (my own hubris and overambition) and now I'm stuck with something too big that I don't have the motivation to finish. It's just too big of a project to juggle now and I'm sorry to everyone who got invested in this.
If anyone wishes, they can continue this story (with permission), and if demand is high enough I'll post a short summary of where the plot was supposed to go.
Update: since some people asked, here we go:
Second arc
The current arc (to the living) is supposed to end with the main cast finding the creature (we will call him Yevgeny). Here's the part I got stuck on: Yevgeny was supposed to be a composite of all the consciousnesses of the followers of Havria, + all the people they tricked into coming with them (hence the invitation Childe finds in Ganyu's apartment), and it wants to absorb Rex Lapis as its final goal in its revenge. I wanted to tie this creature in with Zhongli's regret concerning his past and current failures. I tried (unsuccessfully) to implement him slowly losing his mind due to his mortal body being unable to hold thousands of years of memories, but that failed miserably.
I had no idea what to do with Beidou or Yelan's character arcs as well. I wanted to give them blink-and-you'll-miss-it moments, but could not think of how to implement it. Same for Keqing and Lumine.
As for Childe... oh boy. I didn't plan for him to have too big of a role in the second arc, except maybe come to terms with his feelings towards Zhongli and the resulting disgust from that. Maybe he'd try to save Zhongli from Yevgeny, revealing part of his true abilities.
The only thing I did plan for this second arc is the ending, with a kiss between the two MCs and the beginnings of a potentially tumultuous relationship.
But here's the elephant in the room:
Third arc + ending
I wanted this to be doomed yaoi when I started writing it, but then I wanted them to have a happier ending. This was going to be so much darker initially, with the ending being cannibalism and one or both of them dying. Now I wish I'd stuck to that plan because the current one feels tonally inconsistent. I forced my Greek-tragedy-loving self to write something happy and it resulted in everything from the third arc onwards falling apart.
So here's the original plan: Childe's true intent for getting to Liyue is revealed, where he is sent to collect the remaining body fragments of Rex Lapis. Upon picking up one of the scales, he immediately knows that something is wrong and Rex Lapis is just inhabiting a new body. His obsession with finding something that (supposedly) does not exist puts a strain on his relationship with Zhongli, and this brings out all of his self-doubt and his habit of only loving the people he loves from a distance. He works harder towards his goal so that he can leave sooner, but ends up finding out Zhongli's true identity. I got stuck here as well, but it's going to be somewhat similar to canon with Childe endangering the harbour to get to Rex Lapis; however, he manages to be stopped at the last minute, and the entire truth comes out.
Remember the original contract from the game? Test Liyue in exchange for a gnosis? I wanted something that worked the same, but with the Tsaritsa wishing to communicate with the parasite that is possessing Childe (which inhabits his covered eye). I left ambiguous whether she was human or not, but for some reason or another she cannot communicate with the eldritch horror that is slowly overtaking Childe's body and needs a friend to do it for her, in exchange for a favour she did Zhongli long ago (implied to be helping him retire from his post). Enter Signora, that scene in the bank, etc. etc.
Zhongli goes to talk to Childe on the last night before he leaves, and Childe is still angry but mostly at himself for expecting something good to happen out of what was initially a business deal. This snowballs into a physical fight and Zhongli leaves. They never see each other again after this.
Ending
Timeskip to three or four years later. Lumine visits Liyue and casually drops the fact that she's looking for Childe, who's been missing ever since a visit to his family home. She asks for Zhongli's help, and he agrees.
They enter Snezhnaya, and this part is extremely undefined. I wanted Childe to be at his lowest point, having 'failed' in his objectives to shield his younger siblings from the truth and prevent his job from tearing apart the family. All the while, his body is slowly falling apart and the abyss monster living in his eye looks forward to claiming his soul. All the while, Zhongli can do nothing but watch.
It ends in him deciding that he wants his body to remain his own, removing his infected eye. It doesn't return him to normal, because his being is so intertwined with the parasite that he cannot live without it. He ends up dying, begging Zhongli to keep his memory alive and keep his death a secret from his family. Zhongli eats his still-warm body in a fit of possessive rage.
The final scene is going to be Zhongli, taking on the form of Childe, finding his family home and announcing that he has returned.
Conclusion
So... this was probably too ambitious a project for a student with several exams under their belt. I can't put as much time as I would have liked to thinking about putting all the cool plot threads together, and I feel as though I've lost interest in writing this leviathan of a project. I'm going to stick to smaller projects from now on that hopefully become more self-indulgent instead of becoming too overly complex to try and appeal to the urge to 'subvert expectations'.
Also I hate writing in third person... that may have been a contributing factor.
Cheers.