"So they're... like your world's version of the immortals?"

"....I don't actually know anything about the immortals here? Maybe. I think the most important selection criteria for Keepers is being really smart, and - good at reasoning with probabilities. And having the right personality traits for it, being - emotionally stable even when dealing with things that are upsetting to think about or just super weird." 

"It seems similar to the immortals but the immortals are less-- selected-- although if you cultivate enough that you are immortal you are likely to be emotionally stable, and of course if you live forever you have quite a lot of time to learn things."

"How hard is it, to cultivate enough to become immortal? Is it something where only a very few people have the raw talent, or is it more - something most people could do, if they put enough effort and diligence into it, but it's really hard and so actually doing it is rare?" 

"Most people could if they worked hard enough and started cultivating at a young enough age-- you can't form a golden core unless you're a child, and if you try to form it without proper techniques your core will always be weak. But the diligence required is rare, and many people have other things they would rather do."

"...Oh. So I couldn't try to learn it now, I'm too old?" 

"Unfortunately, yes."

Merrin had not previously thought of herself as someone who would want this badly to have magic powers, if having magic powers were the sort of thing people could do. It's surprising to her how disappointed she is.

"Could I learn how to see qi? ...Apparently that's important for medicine, here. I'm going to need to learn something if I want to be useful as a doctor without any of the support I'd have in dath ilan."  

"All knowledge is useful. If you come from a different school of medicine from a different world, you will have a lot to teach even if you can't sense the things our doctors can. --Non-cultivators can't sense qi directly but it is possible to figure out qi flows indirectly. For example, someone who is bleeding from the mouth is likely undergoing a qi deviation."

"Oh. Wei Wuxian was bleeding from his mouth when Wen Ning found me and brought me to see him. Is that why? It was the one symptom I didn't have an obvious explanation for." She frowns. "He's very sick. I - think he'll probably recover if he's not stupid about it but he seems - like maybe the sort of person who's going to be stupid about it, he was so upset when I said he needs days of rest, he kept insisting he was fine and could go for a run even though he couldn't sit up without help." 

"He is very stubborn and dislikes following rules, and being the most powerful cultivator in the Sunshot Campaign has not helped either of those traits."

"Yeah. I've noticed. It sounds like getting you to tell him he needs to rest isn't going to help much either? Is there anyone he does listen to?" 

"Sect Leader Jiang, sometimes. Master Wen, sometimes, if you can get Master Wen to have an opinion. Myself, if I can point him to a bunch of Wen who need to be killed. Mostly he does as he feels like."

"Okay. Um, please do not try to send him to kill anyone for - actually probably a week. If there's some kind of horrible emergency sooner than that, then...ask me, I guess?" 

"I will let everyone know that as far as Master Wei is concerned the Wen have chosen to spend the next week cleaning their swords and practicing their archery."

"Good. Thank you. I...think in general he's been taking on too much. I understand that he has a very rare skill and it's important to your war effort, but - he's still human. I don't think he has realistic expectations of himself, which doesn't help." 

"If your world has suggestions for dealing with people who are very stubborn in their pursuit of revenge, I would gladly listen, because we have very little."

"It's never come up for me before! I...can try to make the case to him that he would be able to accomplish what he wants more effectively if he paced himself better, but I'm not sure if I expect that to land." Merrin fidgets with the knot of her sash. "I should probably check on him soon. Oh, also, I need more sugar. For his treatment. I don't know if Wen Ning can get me any more, but can you?" 

"Yes, of course, we can requisition it from the Jin. It's quite scarce but the Jin are wealthy."

"I would really appreciate that. And, um, is there anyone else here in need of medical treatment? I want to - try to be useful." 

"Yes, there is, it is a war. If you don't have cultivators where you are perhaps you'd be best with the servants who get accidentally hurt--?"

Nod. "Probably. I want to learn more about cultivators and how their biology is, um, different from normal humans. I do have a lot of emergency-trauma--medicine training." Most of it simulated, but it sounds like she's about to get quite a lot of real-life experience. "I - do need some equipment, I can make do with what's available at this tech level but I'm going to need - bandages, needle and thread for sutures - I'll try to think through all the things I need." 

"I'll tell the supply train to give you whatever you need. --Oh, the food." A servant brings in a few small bowls.

"Thank you!" Hopefully the food is not terrible. Merrin isn't fussy but she isn't sure how good the cooking can possibly be at this tech level. She gamely tries it, though.

There's a noodle soup with meat and eggs and vegetables and edible flowers, a sort of rice porridge with fish and vegetables, assorted pickled vegetables, and a very spicy stir-fried chicken.