"Ooh.  I want a fork.  I want ten forks!  How do people do that?"

"I suppose the knowledge of how to form golden cores and become cultivators could get lost in a few hundred years, if something really bad happened.  Not having undead walking around would be weirder.  Unless it's specifically that swords never get haunted?"

She can't smile, so she settles for twinkling in a hopefully merry way.

"Forking — at least my way, I don't know what is or isn't possible with cultivation — requires special equipment. Once I have my crystal repaired enough to manage it, I'll be sure to offer you the chance," she promises. "And no, we have no undead whatsoever. I'm ... fairly certain that I'm not just back in time, though. For one thing, we have good records of China a few hundred years ago. For another ... tell me, how much do you understand about the very small structures that make up all other substances?"

Yay, forking! 

"Not much.  I think one of the scrolls I read regarding the inedia cultivation technique mentioned something that sounds similar, but I'd been distracted by a different section and never went back to examine it in detail.  Sorry.  If you think its relevant I can definitely listen now!"

"Well, I don't want to bore you. Elementary particle physics was very much my area of scholarly research before landing here, so I could talk about it for hours. If you're actually interested, I can give you a better explanation. But to very briefly summarize, while skipping a bunch of details: all matter is made up of a few fundamental components, arranged in different ways. The valid ways in which these components can be arranged is ultimately a consequence of the underlying physical laws that affect them, plus the shape of the space that they're embedded in. By 'shape' I actually mean something a bit more complicated, but 'shape' is close enough. By watching how the components move, you can make inferences about the shape of the space. Everywhere that my forks and I could observe in our world had exactly the same shape, but the space here has a slightly different shape," she explains.

"And I have no idea why that is! It's really very exciting. But either we somehow forgot about cultivators and undead, and managed to lose a bunch of records without noticing we lost them, and the fundamental shape of space changed slightly ... or I'm not back in time, and instead I'm somewhere else. Which makes equally little sense, because why would you be human, or at least close enough that you react the same way to the medicines I tested, and speak Mandarin? But I still think the latter is less unlikely than the former."

A new thing to learn about!  Wei Wuxian is completely unable to prevent himself from asking more questions. 

"How many fundamental components are there?"

It's so refreshing for someone to want to learn about fundamental particle physics! Mostly people ask her about, like, her duties administrating the fixity crystal network, or her life, or boring stuff like that. She'll answer them, because of course she will, but people seem to forget that she took over the solar system because it was the right thing to do, not because she wanted to talk about it.

"That's a great question! I haven't re-confirmed any of this here, since we don't know if the shape of space is the only difference, so it's possible that the details are slightly different. But I've already seen nine of the same fundamental components, so the basics should really be the same ..."

"Anyway, the answer depends a little bit on categorization, and whether you consider force-mediating particles separately. Also whether you distinguish gluons by color charge. An answer which is mostly correct, in that each of the particles named is fundamental and can't be broken down further, but slightly incorrect in that it doesn't correctly model important non-local forces, is '30'. Other answers that could be considered correct are '18, but twelve of them are capable of moving backward in time' or '32, but three of them can spontaneously turn into each other under some circumstances'. Those answers are actually all different ways of re-framing the same fundamental truth. In reality, fundamental components can be broken down into two categories: fermions, and bosons. Fermions are what make up physical matter, and there are really just three important ones ..."

And Weeping Cherry will give an introductory lecture on the standard model of particle physics — with occasional detours into how non-local effects like fixity fields can be elegantly incorporated into the model, although she refrains from giving any actual details on how fixity fields work — quite possibly until somebody stops her. Or at least until someone interrupts her with a different question.

Wei Wuxian listens intently, grinning and excited, occasionally asking clarifying questions. 

Jiang Cheng is far less interested in fundamental particle physics.  He has just been subjected to a long lecture on it anyway and his patience is starting to fray.

"Thank you for informing my sect brother about this topic," he cuts in during a lull, before Wei Wuxian can ask something else that will start a whole new tangent.  "I'm sure he'll have plenty of other questions on it later, too, but we would be remiss if we didn't offer you the chance to ask questions of us as well."

He is really hoping that the questions will be practical.  This does not seem likely.

...This is going to be his entire life if Wei Wuxian manages to get himself duplicated, isn't it.

"Oh! Uh, yes, I do have several questions of my own," she agrees. She doesn't blush, but only because she's a sword.

"My questions are mainly about how cultivation works — but probably there are some more urgent questions. Let's see ... Are there any particular rules of politeness I should be aware of? Everyone's been perfectly accepting of my current inability to bow, but I am a foreigner, and I'm sure I will mess up something sooner or later. Also, does your world currently have any big problems other than disease, famine, natural disasters, and apparently monsters? I ask because if you have, like, a foreign army that needs a competent translator to negotiate with, I could help there," she offers. "I can also help with the first three things, just not immediately."

Jiang Cheng can handle those.

"Names are the most obvious one.  Everyone has multiple names and honorifics they can be addressed by based on their rank, the relation between the person and the speaker, the listener, gender, setting, intent, and some leeway for personal preference."  He considers preparing himself for a potentially hours-long lecture on the topic and makes a face.  "The most practical option is to just ask which term you should use, or have your holder whisper it to you, until you've seen enough examples to intuit them."

This prompts a proper greeting spree.  Jiang Cheng ought to be addressed as 'Young Master Jiang' and Wei Wuxian as 'Young Master Wei' or 'Wei-xiong.'  Tong-jie likes being called Tong-jie.  Everyone else in the group has wandered off by now, but they get listed. 

"As for problems- The Qishan Wen sect."

"Most cultivators live in sects, and among those sects there are five prominent Great Sects: Qishan Wen, Yunmeng Jiang, Gusu Lan, Qinghe Nie, and Lanling Jin.  The Wen Sect is nearly as large as the next four combined. 

"The Wen used to be decent enough, but in the past ten years have been growing increasingly hostile to the existence of other sects.  Smaller sects in their territory have already been overtaken.  The Cloud Recesses, home of the Gusu Lan, was burned down earlier this year, and they've made a failed attempt to attack Qinghe Nie's sect residence as well."

Weeping Cherry's name is a single unit, but people being familiar have shortened it to "Cherry", and people speaking formally tend to tack on whichever titles are relevant to the situation.

"Eesh; that does sound like a problem," she agrees. "Have you any idea why they're doing so now? Has something changed?"

Shrug.  "No one knows.  Wen Ruohan has been their leader for almost thirty years, so it isn't a case of leadership changing."

"Wen Ruohan has been collecting the Yin Iron for a while - that's a material that generates resentful energy.  If he were affected by it... though from what Wen Qing had implied I'd gotten the impression he was collecting it in order to gain the power to conquer."

Wei Wuxian looks back to Weeping Cherry.  "Ah- I'm getting ahead of myself.  You don't know what resentful energy is.  This will require a basic explanation on cultivation theory.

"In addition to the normal physical energy, there is qi.

"When souls are incarnated and striving towards life and enlightenment, a soul produces spiritual energy.  When they ought to be passing on but are attached to the world by unfinished business, they produce resentful energy.”  As he says this, Wei Wuxian motions with his hands.  At ‘striving towards enlightenment’ his hand reaches upwards of its own volition like a bird taking to the sky.  At ‘trapped by unfinished business’ his hand rises in the same path but this time its as if its being dragged unwillingly by an invisible string.

"Cultivators are people who formed a golden core within their spirit.  Its an organ that creates and stores a large quantity of spiritual energy, as well as allowing us to sense it."

“Exposure to spiritual energy makes people and things ‘better’ - healthier, calmer, smarter.  Taller and prettier, even.  Exposure to resentful energy is the opposite - angry, twisted, monstrous.  That said, I think they’re much more similar than people give them credit for.  Resentful energy is energy.  With a way to shield the body and mind from the damaging effects, it should be just as possible to use as spiritual energy.

"And back to the Yin Iron - it's a material that was created long ago and sealed away.  I haven't exactly had a chance to study it, but it seems to generate and store resentful energy in a similar way that golden cores store spiritual energy.  Wen Ruohan has been collecting it and experimenting with it."

"Interesting!"

Weeping Cherry speculates for a moment about how these kinds of 'energy' could interface with people — but she has not nearly enough to go on.

"I have a lot of questions about how you can actually detect and manipulate these energies, but those aren't directly relevant right now. Is there any way to tell whether Wen Rouhan has been influenced by resentful energy? If you could get close to him, I mean. I should be able to fly in a few weeks."

She can probably develop a way to find out — but it's equally important that the answer be legible to people locally.

"Cultivators can usually sense nearby resentful energy, but there are ways for intelligent entities to hide or disguise themselves.  It should still be readable if someone grabbed his wrist and looked through his meridians directly.  That's going to be a challenge.  Honestly, even just getting into Nightless City is going to be hard."

Wei Wuxian is not at all saying that as discouragement.  He's already thinking of possible routes, methods, and forms of trickery that might get him in. 

Weeping Cherry is torn between helpfully volunteering future abilities and playing coy until her fixity crystal at least has the range to cover (and therefore protect) itself. As she is now, she is technically vulnerable to sufficient brute force.

"I'm certain we could find a way in with a bit of thought," she settles on. "Are there ways to purge someone of the influence of resentful energy? Does removing the energy itself do it, or does it have effects on the body or mind that linger afterward?"

"Definitely.  It's the sort of thing cultivators need to do pretty often, if we run into someone who has been possessed.  It does often have lingering effects, but those can also be treated."

"Hmm. Alright, good to know. How difficult is the technique to learn, would you say? Does one have to be a cultivator to attempt it?" she asks. 

"It depends on the technique.  There are many; the Jiang Sect alone has several that people use depending on personal preference and effectiveness against certain targets.  Other sects have their own.  All of them require the person to be a cultivator.  Not only do they take a lot of spiritual energy, but to even manipulate spiritual energy you need to be able to sense it.  Most can be learned well enough to clear out mildly haunted areas within a few weeks to months, and like any skill they can be improved even once you get the basics down."

"Speaking on a practical and non-hypothetical level," Jiang Cheng cuts in, "telling if he's affected by resentful energy and convincing him to stop is all you'd need to do.  The Wen are famous for their doctors and would be more than capable of taking it from there." 

He does not say 'unless it's your goal to kidnap him and force-purify him,' because Jiang Cheng knows not to give Wei Wuxian ideas, and Weeping Cherry has already expressed her opinion on the rights of patients to refuse medical care.

Then there is a fascinating discussion about the ethics of dealing with people under the effects of mind-altering substances, and the nature of consent, which they will not have.

"Ah, yes, that does make sense," she agrees. "Alright; then that's something to keep an eye on, planning wise. It's always good to have an eye on what problems there are. Is there anything else you think I might urgently need to know? If not, I have some more questions about cultivation — or I could let you rest. Presumably monster-hunting is fairly tiring."

"I can answer those," Wei Wuxian volunteers.  This results in a bit of an argument between Wei Wuxian and Jiang Cheng, but Wei Wuxian elects to ignore Jiang Cheng's objections.

"I've been doing nothing but getting piggyback rides and lying around at inns for the past two days!  I'm as well rested as anyone can get.  And I'm an expert at cultivation theory and research.  Ask away."

"Alright. Speaking as someone offering medical advice, being injured can actually be more tiring than it looks, and I won't be offended or think less of you for cutting our discussion short," she promises. "That said, so many questions. I guess first is some overview of the fundamentals — what can cultivation do? What can it definitely not do? What does it feel like to do it? What is actually involved in cultivating? What are the ways that cultivators can differ?"

Wei Wuxian excitedly talks about cultivation.  It can do all sorts of things! 

Cultivators can send their swords flying through the air without the need of hands to swing them.  They can fly this way, by jumping on top of their sword while they're moving it.  Or floating and flying by themselves, but the sword method takes less concentration so pretty much any time someone travels further than the next rooftop over they jump on their swords to do it.  Sending other things flying or floating, or stopping things from moving, are also possible.

There's a whole sense associated with it.  Feeling places in the world that are good to build on.  Seeing ghosts and other things invisible to normal senses, and tracking them.  This is really good for medicine, since pinpointing exactly what is wrong can be hard otherwise.  It speeds up healing, and can also prevent injury to begin with - the strike that merely got Wei Wuxian a broken rib would have outright crushed a mundane person instantly.

Cultivation can affect the spirit, both incarnated spirits and ghosts.  Songs that can soothe or enrage emotions.  Control of others - Wei Wuxian has a talisman he invented that lets him order people to do basic tasks that they find simple enough to do without thinking about them.  He maybe gets distracted talking about it - how he tested it on Jiang Cheng back in Lotus Pier, and how he got beaten after using it to force the Second Jade of Lan into getting drunk. 

Heating places.  Cooling, but that's way harder.  Light.  Silencing spells and privacy talismans.  A bunch of talismans for sending messages long distance, if the person knows exactly where to send it to or knows the recipient well enough.  Qiankun pouches where the inside stretches to hold lots of things while the outside remains tiny. 

Normally it takes a cultivator to activate a talisman, since it's hard to do it blind, and many talismans are just normal ink that requires a cultivator to put energy into it.  But there are pre-charged talisman inks and ways to activate certain ones.  Most famously talismans that react to being burned by stopping all fire around them - they sell those to libraries.

The only thing more interesting than what they can do, is what they can't do ...yet!

No one has worked out going back in time, or stopping time.  Seeing the past other than through what a spirit who was there can show them.  Seeing the future.  Reviving the dead - though in theory if you had the soul and an intact body it should be possible. 

Things that it can do but are hard... there are stories of people traveling to the underworld or the heavens and returning, but none have been in the past thousand years.  Maybe the knowledge was lost, maybe the gates to those realms beefed up their security, or maybe they were just rumors and tall-tales.  Immortality: someone manages it every few decades, but it takes being extremely powerful and also extremely in control of oneself in a way that almost no one can do.  Immortals can fly as high as they want but everyone else is stopped at a point due to needing to breathe.

There are other limits.  Lots of them are just not having enough power - Qiankun pouches are one of these.  In theory a well-made qiankun pouch could hold a mountain, but it would take so much spiritual energy that a whole great sect could exhaust themselves utterly and it would only keep the mountain stored for a few seconds.  Others are limited by the amount of 'oomph' a cultivator can send out at a given time, like flight speed.

It feels like... well, the spirit is part of the body, so it's mostly like using the body, but also like moving a liquid.  So kind of like partway between your limbs being a hose that's being used to redirect water and part just like how when you're exercising and shifting your weight from one leg to another?

It involves lots of meditation!  Meditation to gather energy, to collect it.  And meditation to keep the mind stable so it doesn't go out of control.  Also martial arts - the sword forms and katas and other movement of the body is vital for getting the nascent golden core "spinning" the right way and is good for it afterwards too.  Being healthy and fit is important - cultivation and body and mind all reflect on each other and when one goes wrong the others tend to follow.

Every sect has some variation in their techniques and specialties, and individual cultivators specialize into jobs and narrow focuses of study even within those. The Nie use sabers instead of swords.  Wei Wuxian doesn't know how much of the differences between people from different sects are genuine cultivation differences and not just differences of people raised in different cultures.  Everyone can use the same skills, if taught - every sect has secret techniques they teach only to their disciples, but there aren't any techniques that only certain people are inherently capable of.

Weeping Cherry takes notes and asks insightful questions. Cultivation really doesn't sound like a way physics should work, but Wei Wuxian clearly clearly believes what he's talking about. If only she had a slightly larger range, to try and capture and experiment with some spiritual energy ...

In any case, that all sounds fascinating. But she should prioritize a bit. She briefly ponders which follow-up will give her the most information to work with, and ends up deciding to ask about talisman design. How are designs made? Are there patterns or commonalities between different designs?

If she's lucky, they'll be something like circuit diagrams, and she can just write a backend for her self-tree's preferred hardware definition language. If not, it's no big loss, because everything to do with Cultivation is interesting anyway.