The Qing Jing trio but they're dating. Somewhat. At least BingFan are. Ning Yingying has a queerplatonic thing going on with both of them.
Like for some reason BingFan are co-head disciples and constantly trying to one up each other (in a very homoerotic way mind you). NYY feels left out so she secretly takes lessons from LQG so she could be on par with both of them.
This leads to her cultivation significantly improving and she can even topple MF over in a sparing match. LBH of course tries to give a backhanded remark before promptly getting thrown to the ground by NYY too.
Eventually when the Conference arrives and NYY actually gets selected too. All three go together and when the canon event happens, MF tries to pull LBH up but falters. They both end up falling in and NYY tries to pull them both up but ends up falling in too.
SQQ is panicking because "ohhhh fuck oh fuck. Ning Yingying and Ming Fan are going to die there. Of course LBh will be fine, but those two?"
Anyway he goes back to Qing Jing and does his whole mourning thing, and then all three come out and take over the demon realm.
SQH is the first to find out and was like "What... What the fuck?! That's not supposed to happen?!"
Eventually they go to Qing Jing and give SQQ the scare of a lifetime. Soon he gets used to it because aww his little ducklings are back 🥹
Just ignore that now all three can bring fear into a demon's heart. They're just his little babies. It's so unfortunate that he missed Ning Yingying and Luo Binghe's marriage :(
I've been toying with a "third transmigrator" AU for SVSSS in which the third transmigrator is a teenage girl who ends up in Luo Binghe. This teenage girl tried to read PIDW because someone else liked it, but didn't get far because she didn't like it.
Disinclined to follow the plot, the teenage girl decides to transition, because fuck it (crying breakdown), she doesn't want to be a guy. Ning Yingying is initially the only one in on it (and then some Qian Cao Peak people). This new Luo Binghe knows JUST enough about the plot of PIDW to avoid Shen Qingqiu's attention as much as possible and so swears Ning Yingying to secrecy regarding the transition. She intends to hide it until the Transmigration System lets up on the missions and restrictions a little.
Meanwhile, Shen Yuan is like, "How am I supposed to improve my relationship with the protagonist if i never see him? Did he just jump out a window to avoid me?! Also, hmph, the bullies are all calling him 'Luo-Shimei' now? Just because he's pretty??? I had better go tell them off for it!"
(Shen Qingqiu, please, your students are getting the impression that you're transphobic!!!)
If Luo Binghe's transition comes out before the Immortal Alliance Conference, Shen Yuan is going to 1) think it's his own fault somehow and 2) be more than a little weird (and a little transphobic) about it.
Shen Yuan (internally): "Oh, shit, NOT abusing the protagonist turned him into a girl??? How does that work???"
The endgame relationship here is a messy love triangle between Luo Binghe, Ning Yingying, and Ming Fan. Ming Fan is like, "What do you do when the shidi you hate falls down the stairs and nearly dies, and then apparently can't remember you used to bully him and expects you to be a good shixiong, and becomes best friends with the girl you like but also starts turning into a cute girl too??? But you can't tell Shizun any of this otherwise the girl you like will kill you???" Ning Yingying is like, "I was so caught up in the thrill of makeovers and having a new sister that I forgot to examine why, when she's approached by guys, I want to tear their throats out with my teeth. Ming-Shixiong is not good enough for A-Luo!!!" And Luo Binghe is like, "Wow, Ning Yingying is such a good friend. And so pretty. I could stare into her eyes for hours. Ming Fan is kind of a jerk sometimes, but he's cute, I guess. He needs to shape up if he wants to win Ning Yingying's heart someday! She married a guy, so she's definitely into guys."
This third transmigrator isn't paying too much attention to their own love life partially because they're too busy 1) trying to survive, 2) trying to do right by their friends, and 3) trying to figure out if Shen Qingqiu and Liu Qingge are in a "toxic yaoi relationship" and, if so, which one of them tops more frequently and where Yue Qingyuan fits into things.
If you haven't guessed yet, this third transmigrator is actually Shen Yuan's younger sister, who transmigrated at like 16 years old at the oldest. This identity reveal comes out at the Immortal Alliance Conference, seconds before disaster (the push into the Endless Abyss), and no earlier. It does not go well. The Transmigration System is mostly to blame.
Live Shang Qinghua Reaction: "Oh, fucking yikes, bro."
This Luo Binghe hands a lot of control over to Meng Mo to get out of the Endless Abyss. An inadvisable amount of control, really, even if Meng Mo is soft on the girl. Afterwards, they sort of stumble into the arms of Huan Hua Palace. Shen Yuan's sister did not read far enough to know pretty much anything about this sect, especially not that it's a terrible idea to be here while being both a Heavenly Demon and (post-transition) looking like even MORE of an identical clone of Su Xiyan.
(Tianlang-Jun and Zhuzhi-Lang ARE both going to be kind of awful and weird about it, yes, at least initially.)
Gongyi Xiao, after showing basic kindness to this poor young woman: "Hey, why are those two Qing Jing Peak disciples glaring at me like they want me dead?"
That princess x knight trend but the princess is NYY and the guy she's marrying is LBH and MF is the knight (aka just there bc Cang Qiong was invited) there's three possibilities
NYY and LBH both look over at MF, catch each other and immediately start arguing on who has the right to yearn over MF in the middle of the wedding
Only LBH looks over and he sighs pathetically (NYY is unimpressed)
NYY and LBH look at MF together, but this time MF gets a chill down his spine (they're both cracking their shixiong tonight)
Ignore me for a moment I'm having bingyingfan thoughts (mostly in relation to my previous post but this is actually meant to be nonplatonic or you can see it as a qpr I don't mind either)
Them at their wedding night and they're getting undressed and LBH finishes first. And NYY and MF just pause and go "absolutely fucking not 😨🤝😥". And they postpone it until someone says they could just top LBH and they go "wait..." "Oh yeah." Luo Binghe is quite happy with the arrangement.
NYY and LBH teaming up against MF to torment him and his poor bi sensibilities. He's trying to escape but they both have him sandwiched between them while sweetly calling him "shixiong". MF not dealing with it well.
NYY and MF naturally flanking LBH whenever they go anywhere together because they had to stay in that formation while in the abyss so often that it's been ingrained into their subconscious. And LBH feeling incomplete if either one isn't there at his side.
NYY and LBH arguing (jokingly) about who would be the "wife" in their trio. NYY insists because she's the only girl that she's the official wife. LBH retorts that he's the homemaker so he is the wife. MF doesn't join the argument, but he is usually dragged into them to pick. He picks neither and hides until they stop pouting.
LBH being the resident cook and MF being the one to always make the tea. NYY is quite spoiled by them, but usually insists on cleaning so she doesn't feel useless.
Some demon asking LBH who's his primary spouse/empress and who's the secondary spouse/concubine and with a straight face LBH says "No, I'm the concubine." And then leaves without explaining himself.
LBH brings dead beasts as gifts for NYY and MF. Usually to cook them dinner or make something from the hide. That's to say, he got really good at sewing and most of the stuff NYY and MF wear are made by LBH. And maybe the official tailor.
MF tends to make paintings of LBH and NYY. He doesn't give the majority of them to his spouses because he doesn't think they're up to his standards. When they find the drafts drawer they have a field day seeing the moments MF thought were important enough to capture on paper. Most of them are sweet domestic moments or them fighting. MF is deeply embarrassed when he finds out they saw the drafts.
NYY makes crafts and sometimes weapons for them. Their sword ornaments are completely made by her. And MF has an obsidian dagger hidden on his person made by NYY. LBH had a crystal hairpin made by NYY he tried to use but it got lost in his hair, so he asked her to turn it into a pen. Now he has a favorite crystal pen that he uses for his diary or notes he writes to MF and NYY.