Suddenly started thinking a lot about Mu Qingfang lately, and I feel like there's so much Potential there. Idk I've developed some headcanons that may or may not eventually become part of a fic.
I don't know if every peak HAS to learn how to fight, but several of them canonically do, even those with other focuses (such as Qing Jing). So it's reasonable to assume that even the medicine peak at least learns basic self-defense.
So in my head I figure (esp. Considering it's a literal different world) that the expectations of what a doctor should or shouldn't do would be a little different. If these disciples are meant to be something between a doctor and a fighter, I think their discipline would come out looking like something akin to if doctors were required to complete their residency training as combat medics.
Which means the Hippocratic Oath and related regulations would probably look very different there. I think Kill If Necessary and Not Everyone Deserves Treatment would be acceptable philosophies. I headcanon Qian Cao disciples would be trained to be efficient in both ends of the medical practice: healing and harming. After all, the saying goes: the dose makes the poison. When learning to heal someone, you also learn how to kill them.
Which is basically to say, I think Mu Qingfang (and his disciples) are just as much a poisons peak as they are a medicine peak. If they're meant to have combat experience/training, I think they'd also learn very quickly to always be prepared and always plan ahead, especially if a one-to-one fight isn't their strong suit. This would make Mu Qingfang a very shrewd and cunning person. He's perfectly friendly- was made head disciple for his impeccable bedside manner- but that friendliness was trained and is also partially calculated. He's not the smartest peak lord, but a man like him wouldn't leave things up to chance and faith.
My headcanon for him is that he grew up in poverty, and likely saw a lot of death and illness during his childhood. This drove him to dedicate himself to medicine, but I also think the dangers of growing up in a rough environment made him naturally wary of everyone, especially those with lots of power, be it financially or physically etc. I think this eventually causes him to develop a habit of creating "backup plans" on what to do if powerful people try to hurt him or others, even if he's friends with them.
I think they start as general "oh I could use x as blackmail on this guy" or "I'll ruin her social life" kind of strategies that usually just end with the person being sent away somehow (forcing the neighborhood bully to move, sending a man to jail, just shaming someone hard enough to keep them from showing their face again).
Once he starts at the sect, I think this would evolve into figuring out how to eliminate someone. Cultivators can get away with a hell of a lot. Especially the ones at the top. Normal prisons don't hold them, and sects tend to close ranks around perpetrators and brush the misdeeds of their favored members under the rug. Not any different from any other organization, but it can be far more dangerous when the perpetrators are literally junior immortals. So, eventually, disciple era Mu Qingfang started brewing poisons and growing plants designed to target cultivators.
Not always how to kill them; he doesn't actually even like violence! In fact, learning how these plants interact with human qi has been monumental for advancements in medical treatments. He's just as enthusiastic to discover the ways in which the roots of one plant interact with the leaves of another to create a soothing balm for rashes caused by mild demonic qi poisoning!
It's simply instinct at this point to also note the ways in which it can cause disruptions in qi flow or restrict the trachea. He spends almost as much time learning how these medicines can be repurposed for getting rid of problems. Some are designed to destroy a person's cultivation core, or tangle their meridians, or leech off their qi just enough to keep them weak for really long time.
To that end, I can imagine this version of Mu Qingfang having an entire study dedicated to what to do with Luo Binghe. The second it was discovered that Binghe is half heavenly demon, Mu Qingfang breaks out all the tomes he can find that even allude to them. Diagrams, diaries, old artifacts. He can't use Binghe as a live test subject, but I think he'd work around that by learning as much as he could secondhand. Binghe has both demonic and human qi; this suggests 2 cores, or a singular hybridized core that can produce both in turns. He controls or traces people with his blood? Main theory is blood bites, like an overactive immune system he can manually command. His dual qi also causes double immunity from substances that infect or leech his abundant qi? Then it's likely he has 2 cores instead of 1 hybrid, and may even have extra or more robust qi pathways to compensate for the burden.
Conclusion: the main obstacles to taking down a half heavenly demon are the mites, the 2 qi types, and the abundance of qi. Poisons that are most effective would either target the mites first, or would be able to slip by them undetected before attacking the meridians. If mites are like semi-sapient white blood cells, it was unlikely he could effectively create a poison that would go undetected by them without testing it first. So he'd have to focus on a poison that could kill or temporarily decommission them instead...
When Binghe kidnaps Mu Qingfang to look after Shen Qingqiu's corpse, he's aware enough of the boy's intentions to not be hostile towards him. Even so, being at the mercy of an all-powerful being solidifies his conviction: he will make a poison capable of felling even a heavenly demon. Upon his return to Cang Qiong, Mu Qingfang gets to work.
