#sxy

Pre-narrative I would say that Tianlang-jun and Su Xiyan filled fairly stereotypical demon and cultivator / magical girl roles. As head disciple for Huanhua Palace Su Xiyan is definitely a magical girl who has a full transformation and abilities! She's probably the glamourous leader of her magical girl squad, she's the one on the centre of the box art! She definitely has a lot of experience fighting the monster-of-the-week hoards of demons in classic magical girl style!

And Tianlang-jun definitely had the ability to do a full demon transformation — I think Heavenly Demons can do it innately, they don’t need transformation accessories like other demons do (LBH needed Meng Mo in the PIDW!version of the story to kickstart his ability to transform, but after his seal was broken and he ended up in the Abyss he would have been able to do that innately as well) — but only the sort of transformation expected for a Heavenly Demon. Which is, frankly, scary enough!! But everyone knows that humans can't transform like demons, and demons can't transform like humans.

My thinking is that while Tianlang-jun may be more interested in human culture than a standard demon, he still is, inherently, a demon who lives within the social constructs of demonic society and nature. He definitely has a love for life! He has things he’s passionate about! He’s even fairly trusting… but less in the “I give you my entire heart and trust you with it even if I get hurt way” and more in a “I’m the biggest, scariest predator around, so what do I really need to be scared of?” He confident and having a good time! But that isn’t quite the same thing. In this au I’m proposing that demons don't tend to form social bonds to the same degree that humans do. They are capable of different forms of love! But they tend to be more solitary and individualistic, the pack bonding is nowhere near as strong as in humans.

I'm assuming Heavenly Demons don't tend to form strong familial bonds (otherwise PIDW would absolutely be run by a dynastic Heavenly Demon reign pre-LBH, they don’t seem to stick together and we don’t really hear about the previous generation of Heavenly Demons). Tianlang-jun has some vague kinship with his sister, but there’s no real love lost, and he has passing affection for his nephew but not in a way or to a degree that a human magical conduit would likely be able to work with. It's how demons work! No one is dissatisfied with this! Though this fundamental difference definitely contributes to the human bias against demons, seeing them as entirely “heartless”.

Except then we get the unique mix of a Tianlang-jun who is interested in human culture and art… and therefore their depictions of love and romance, and a Su Xiyan who meets him and doesn’t immediately try to kill him. It starts with fascination, but eventually this absolutely becomes a degree of love and trust between both of them that they couldn’t have predicted.

Tianlang-jun’s sole instance of magical girl transformation comes from a moment when he finally convinces Su Xiyan to let him see her transformation accessory. The idea of a demon getting their hands on one (rather than it breaking with its bonded magical girl’s death) is unthinkable for both cultures, honestly, and Su Xiyan guards hers carefully any time she’s with him, vaguely wary of betrayal… until she isn’t. Tianlang-jun has no malicious intentions, this is just something incredibly personal and important to her, so he wants to understand it.

She passes it over to him.

And he transforms — not like a demon, but like a human, full of love and trust.

Which has world rocking implications for both of them. Culture mores and biases for both would mean this doesn’t even seem like it should be in the cards. And it makes Su Xiyan, who is already having some uncomfortable thoughts about her own biases against demons, realise exactly how fucked up humans may have things. This revelation and new conviction leads to a cascading chain of events that eventually ends in the Old Palace Master locking her in the Water Prison and Tianlang-jun being led into a trap. We know how this goes.

After this point he is unable to transform again, for rather obvious reasons (similar to how Shen Jiu might have had the magical potential, but had his trust broken so severely that the magical connection couldn’t be formed anymore). He trusted someone with his heart and, as far as he knows, she immediately used that moment of vulnerability to crush both him and his heart under a mountain. In the SVSSS!version of the story, he’s definitely scornful of his progeny going around using a magical girl style transformation instead of relying on his Heavenly Demon form. Truly this unruly son of his is shaming himself and all demons!