WOW okay that's a stupid way to organize things. Perhaps there should be warning signs? A moat? Less aggressive armament issuing policies for the next Nie generation? At any rate she can pass this information back into the present once she has it.

They have methods to try to keep people out! That's what all the rumors about horrible things on the ridge are for, and labyrinth array, and so on. It works fine when you don't literally blow up the walls to get inside!!! Who does that???? This is the first time it's ever (counterfactually?) happened!!!

Okay, fair, blowing up the walls to get inside is kind of a weird thing to do, why did Jin Ling do that. STILL, WHY ARE YOUR SWORDS EVIL.

The same family cultivation tradition that's why sect leaders keep having horrible qi deviations and dying, ok, Nie Mingjue wasn't the first one, there's a reason Nie Huaisang decided to make a lifestyle of being useless and also pathetic at his family's cultivation style. Admittedly though it is a really effective style, most Nies are just...more willing to trade off lifespan and post-mortem weird saber tombs for effectiveness at putting down evil. 

Wei Wuxian would like to note that there are actually distinct similarities between the techniques Nie Huaisang is describing and demonic cultivation, which explains a lot about why this isn't more widely publicized and they don't want to tell the truth about why people should stay away. 

"Is there a really bright line in the first place?" she wonders.

"Normal cultivation involves using your own spiritual energy. Demonic cultivation involves directly manipulating external negative energy. Normally they're just completely different. The Nie infuse their sabers with negative energy from the things they kill, which...toes the line, but I imagine even if it did come out they'd get a lot of slack for the thing where it's a traditional method of a powerful sect." 

"Is there such a thing as external positive energy?"

"Oh, sure. Everything alive has it. Places of spiritual power build it up naturally. But messing around with it would get you even harsher looks than messing with external negative energy--at least nothing's using that that anyone cares about. In theory you could get really powerful fast by absorbing lots of external energy all at once, but first you'd have to figure out how to do it, and then you'd have to figure out how to do it without fucking up everything alive within a certain radius while you did, and then you'd have to figure out how to fend off everyone who'd call you some kind of horrible energy vampire. Inventing demonic cultivation was actually easier than that would have been." 

"Huh. I mean, if you sucked the life out of some kudzu, who'd mourn the kudzu, right... or do you mean you'd have evil kudzu afterwards somehow..."

"The kudzu wouldn't be immediately, inherently evil, but it'd be a lot easier for it to become evil than kudzu that had died some other way, and also, if you can do it to kudzu, you can do it to a person." 

"If you can stab a zombie with a sword you can also do that to a person!"

"Yeah, but the people who might get scared and violent already know how to defend themselves against that. It isn't new and heretical and interesting to spread negative rumors about." 

"Bleah. Anyway, do we need more information or is this enough?"

"We should ask him if he knows anything about any malicious dismembered body parts." 

What will he have to say about those.