SVSSS Mermay au - siren song
Now, and I went to fact check this, in H2O siren song is actually a very limited ability that (usually) only born sirens have, and even then it's a limited part of the populace. Mermen actually have a shockingly low amount of rights and rights to merpeople abilities. Does Xiang Fei know or remember that? No, but he'd assume it only works on mermaids anyways and the System ran with that.
However, mermen in PIDW do still have some singing abilities, in the sense that their voices are very melodic by nature, even though they do not possess the ability to put men under a thrall. Mermaids, on the other hand, do possess that ability, so the general (human/demon) populace would assume they all possess the skill as a species.
What this means for this AU tho is that Mobei Jun, after finally researching merpeople finds all these stories of sailors and lake dwellers who talk of the enchanting songs of the fish people who will use their Song to pull you deep into the depths of water and steal your life away. Now he looks at his servant and thinks to himself that there's no way such a thing is actually true because... well. Shang Qinghua is not really that much of an out-of-this-world beauty with a "voice that always carries a part of the Song and makes you unable to think straight in their presence".
That is, he doesn't believe the rumours until he comes upon his servant humming while doing paperwork on An Ding peak. The song is unlike anything he has heard before and has an almost dream-like quality to it that makes him want to stand there and listen to him forever.
Considering this is still pre-plot era, he has an entirely normal and logical reaction to this fact--as in he panics and runs away the moment Shang Qinghua looks up at him with a soft "My King?". He does not return for a week. The whole week is spent thinking about that moment and researching ways to stop enchantments because what else could that feeling be? Surely it must be some powerful magic to make him feel this way. He must find a way to nullify it and punish his servant for trying to enchant him like this!
Shang Qinghua spends the whole week very confused and anxious because His King just? Took one look at his singing and was so horrified that he had to leave? Is his singing so bad that even humming made Mobei Jun run away!?!? He knew he'd never win any awards in his past life, but man, why did the System have to punish him in this life too!? Life really is never fair to this poor author...
