Im going to write masayou soulmate aus and no one can stop me but at the same time im not the best writer so maybe ill just toss my ideas out here for now. Void write this down because im gonna have to come back to these.
This is a long post im sorry
First au will be the colorblind one where you see color once you make eye contact with your soulmate for the first time. However, platonic soulmates exist thus causing more confusion. One thing that helps is that the effect romantic soulmates have is much stronger while platonic soulmates tend to just help with vibrancy or seeing some colors. (Im just winging it here because honestly masahinashiyou are def soulmates).
Anyways, this is how its gonna go: youji and masaomi meet in the usual i saved your life way we’re stuck together except both can see colors pretty darn well now. For youji it was kinda a brief explosion of color followed by dimming except for the colors red, gold, and purple. Its similar for masaomi except the vibrancy is slower to come for him but it starts with blues and metallics. Masaomi naturally has to keep this under wraps because he needs to know who exactly this guy is and what type of person he is and he also doesnt believe himself to be a romantic of any sort. Is he capable of being romantic yes of course but will he ever do anything like that now? Not unless the person had earned his respect and seemed worthy.
Oh no this could be a multi chaptered thing
Anyways this sort of goes along with his slow burn sort of thing whereas youji is kind of just that type of person to help out masaomi without needing proof to accept that masaomi is an important person in his life (the cult really watered down the whole soulmate thing because theyre homophobes so its just “important person in your life” for them). The colors also represent his “oh no hes attractive” side of youji who secretly has it pretty damn bad for masaomi.
They both stick with each other because they both recognize that theyre going to be important to each other (though currently only masaomi has an inkling as to how important they are/will be to each other since his vision is not terrible and that brief explosion of colors was no mistake, he simply isnt/wasnt ready to trust youji fully and also the universe was giving him a challenge and a choice which he will not back down from thank you very much) and youji wont realize what the colors and vibrancy mean until he meets hinami and shiori who are more than welcome to discuss those with him.
What happens when shiori and hinami meet them? For shiori and hinami, the world becomes more focused when theyre by each other and small details and colors pop out more. This is especially true for hinamis side since shiori brings clearer perspectives and other points of views to the table. For shioris side hinami brings out the brighter lighter and softer colors of the world that one might miss. Masaomi brings out the bolder colors and youji stabilizes the “image” and brings both color types into balance. For youji hinami brings all the colors into focus and its breath taking but also for the most part the colors were already there. However light seems to hit everything he sees now and wow you mean light causes different shades of things? Shiori doesnt seem to change much but he does notice that certain colors look more saturated or that he can see certain textures now and differentiate between certain shades. Especially in the blues, purples, and greens, hinami works mostly with the warmer colors. For masaomi he hinami doesnt change much for him although he does realize how he remembers the details of people and earthy tones more easily after meeting her. Shiori balances out the saturation and brings forth the colors that refused to come out before or simply just needed a push to come forward. Of course shiori also comes with pushes towards youji.
Oh goodness this is so long. All this detail is unnecessary but its here. It ends with them all agreeing to OT4 after hinami and shiori wrestle feeling talk and misunderstandings out of masaomi and youji. Youji totally thinks masaomi is an unrequited/not reciprocated love after all and/or JUST FRIENDS. But really masaomi is like “of course im going to be with youji forever thats been decided since i was 18. And shiori will be there too but she was a more recent addition to my life. I guess hinami can come too” but hes just been quietly planning this and thought that everyone else was on his level and knew already. And it ends happily ever after (except eventually shiori and hinami die and masaomi and youji drift apart but then they come back and kasamatsu comes across pictures of all of them and asks about what happened and does some snooping and finds out his dad and masaomi were soulmates and has to work with kise to get them together again but kise mostly just wants to do it so he can get more alone time with senpai but then akashi interrupts and furihata is a romantic and is all for it and also cites the manga a lot for help and youji is embarassed because his son is insisting and pulls out the “this is what mom would want” card and they talk about hinami and shioris deaths and what that means for them and their feelings and masaomi FINALLY admits to how he didnt like living without youji and youji admits that he wished masaomi was around for more of his familys life even tho masaomi cringes because babies and kids but does admit that had masaomi been around they would probably be much greater than they are now NOT THAT THEYRE BAD OR ANYTHING JUST LIKE OK HE’LL SHUT UP NOW but that youji could somehow make kids look appealing. In a sense. AND THEN it finally ends happily ever after omg.