Sanitize

Fanfiction
Title:	Sanitize
Author(s):	Sage Thrasher
Date(s):	April 3, 2017–Ongoing
Length:	67,500k
Genre:	OC-Insert
Fandom:	Naruto
External Links:	on fanfiction.net AO3 Archive link
Click here for related articles on Fanlore.

Sanitize is an OC-insert Naruto fanfiction by Sage Thrasher about an original character who was a modern-day doctor in her past life and is reborn as a peasant in a small village in the Land of Fire in the Warring Clans era.

The summary on fanfiction.net reads:

Basic medicine and sanitation are simple. During the Warring Clans era, they become revolutionary. [OC-Insert]

As of May, 2019, Sanitize has 2,637 favorites, 8,329 follows, and 2.527 reviews on fanfiction.net.

Contents

Sanitize follows its main character, Yui, starting at around the age ten when she's jolted out of her peasant life with a memory of how to set a dislocated shoulder and begins to grapple with her remembered medical knowledge compared to what her small, pre-Industrial peasant farming village has access to. Yui sets out to do what she can with what she has, focusing on improving sanitary conditions and basic medical knowledge and maybe, if she's lucky, proving the germ theory of disease and develop penicillin.

Yui quickly finds that due to her village's location she has plenty of access to merchants and patients, but she's also unfortunately right between the bitter blood feud that the Senju clan and Uchiha clan have been engaged in for generations. Yui brings economic and social change to the region due to her radical view on healthcare and information, mainly that both should be free and easy to access.

Major themes focus around Yui's narrow view of the Warring Clans era and her even more narrow effect as she seeks to triage or solve problems she didn't cause and has no easy answer for. The difference between internal and external lives is also stressed, so there's focus not just on how Yui views herself as compared to how people view Yui, but also how non-ninja view ninja compared to how ninja view themselves. Sanitize features a great deal of worldbuilding and original characters, as the Warring Clans era isn't very fleshed out in Naruto canon.

Original Characters

There are more recurring OCs than are listed here; these are only the most plot relevant.

Yui

The main character. A doctor in her previous life, she now struggles as a Land of Fire peasant to provide medical attention to anyone who needs it despite not having the tools and infrastructure she remembers from her previous life.

Sen

Yui's younger brother and apprentice.

Eiji

Yui's apprentice and Sen's best friend.

Dr. Makoto

A doctor who was trained in the capital and met Yui when she was first starting out as a healer on her own; he reconsidered his own gender biases and medical knowledge following his first meeting with Yui and came back about a decade later to ask her to teach him.

Tsubaki

A merchant who largely deals in glass and travels to Land of Wind and around Land of Fire regularly; she helps Yui get the glassware she needs to start trying to make penicillin. She also has a Hatake bodyguard.

Canon Characters

Characters in this section are described with regard to their role in this fanfiction, rather than summarizing their canon roles.

Senju Hashirama

Senju clan heir and accomplished healer; seeks Yui out as a friend often after they bond over wanting things to be different. Wants to rekindle a childhood friendship with Madara so they can reach peace together. Becomes clanhead after his father dies.

Senju Tobirama

Hashirama's younger brother, a suspicious and sharp ninja; he and Hashirama have a great deal of tension around Hashirama's dreams of peace. Tobirama is somewhat slow to be won over by Yui.

Uchiha Madara

Uchiha clan head and childhood friend of Hashirama; through interacting with Yui and because of her mostly-unrelated dealings with the Senju, he comes to hope that his and Hashirama's dream of peace might not be dead after all.

Uchiha Izuna

Madara's younger brother, and completely unwilling to believe in peace so far. Madara says that his refusal to consider peace stems from the death of their younger brothers at the hands of the Senju. He and Izuna seem to have less outright tension regarding the peace than Hashirama and Tobirama, but they still definitely disagree.

Also briefly making appearances are: Senju Butsuma, Hashirama and Tobirama's father; Senju Touka, a Senju clanswoman; and Senju Kawarama, Hashirama and Tobirama's younger brother.

Excerpts

[Chapter 1]

The ninja were murderers, surely. Yui had heard all the stories. Assassins for hire, mercenaries willing to fight for any lord, men who could summon fire and storms... many considered them to be the children of demons. At the very least, they were callous and unconcerned with collateral damage. But if Yui did not help, they would die soon. The boy's chest barely rose, and the man had lost a great deal of blood. She had a responsibility to help and heal. Didn't she? Yui's memories of her last life blurred with her present one. She'd taken an oath. Had she?

"I… yes," Yui said. "I will heal them." She glanced and the village elders and added, "But that's it. I won't offer any sanctuary. They'll leave after that."

Elder Dai nodded, satisfied. "Very well. This village is no place for you, shinobi, but our healer has offered her help."

The ninja's shoulders sagged further. "Oh, thank you," he croaked. "I am in her debt." He did not say another word as he followed Yui to her hut. She couldn't help but wonder if she'd made a mistake by deciding to help him. All the same, she methodically tended to their wounds.

[Chapter 4]

"You taught her chakra healing?" interrupted Tobirama, voice rising just a tad in pitch. His face was deliberately neutral as he glanced from Yui to Hashirama.

"I did. It was the least I could do." Hashirama didn't look at his brother, but his voice was hard. "Yui-san, you were saying?"

She blinked, pausing for a second as she tried to recall her train of thought. "Ah, yes. I was wondering about whether your chakra healing kills infections."

"Infections?" Hashirama frowned, eyes half-lidded in concentration. "What do you mean?"

Despite himself, Tobirama grudgingly added, "And what does that have to do with chakra healing?"

"Does it… does it kill what causes the infection?" Yui continued on, picking up steam. "Because, if the healing just makes the skin grow back and cover it, then the, um, the cause of the infection—"

"Miasma?" asked Tobirama.

[Chapter 6]

"But the village has fared well?" said Madara, sounding a tad exasperated.

"Er, uh… yeah." Sheepish, she put an empty jar aside to be refilled. "They were all taken care of."

"Really." His dubiousness grated on her nerves, but that was tempered by his expression of disappointment. "So you don't require any assistance in that regard?"

Yui thought of the hand that had appeared on her doorstep. "No, but thanks," she said dryly. He'd have to pay the old-fashioned way.

With one of his usual not-a-sighs, Madara dropped a bag of coins on the table as Sen returned with the extra jars. Sen placed the jars on the same table and stepped back, standing just behind Yui.

"Much appreciated, as always." Madara gathered the jars into a simple sack.

"Wanna stay for tea?" asked Yui, fully expecting to be rejected, ignoring how Sen grumbled and Eiji looked rather pained at the thought.

"No."

Inspiration, process, and development

In a 2016 tumblr post — before Sanitize was published — Sage explained how she approaches the Naruto universe and its many moral challenges:

A few people have asked if all my characters hate the Naruto world and whether or not that reflects my own views on the matter. First, I’m going to reiterate my disclaimer: my OCs are not me, and I do my best to create fully-formed characters that may have opinions wildly different from my own.

Elaborating on that… no, I don’t hate the Naruto world. There are a lot of things I don’t like about it, both from a moral and “literary” perspective. I’m not the biggest fan of the whole dictatorship and child soldier thing. I’d much rather live in my own world, in a country I love with the people I care about. However, I’m very much a pragmatist/realist. Sacrifices have to be made, sometimes. To get anywhere in life, you have to negotiate with people you don’t like or agree with. Nuance and looking at issues with a case-by-case basis is important to me.

In response to an ask, Sage discussed her direct inspiration for Sanitize as well as how the idea changed as it developed:

...Sythe’s From the Garden of the Gods AU[1] was actually the fic that inspired the whole shebang. It got me thinking about how a regular (non-magic) medical professional would make an impact on the Warring Clan’s Era.

It’s interesting how these things happen; Sanitize was originally going to be an expy of the MC from Mind the Gap[2] in a different era, but as I started plotting things out, Yui and the story took a whole new life and is now completely unrelated. Inspiration comes from many places, I suppose.

In response to an ask about if she would be diverging from Yui's point of view, Sage explained that she wouldn't be using other characters' POVs and that it's "a conscious decision; I want to emphasize the limits of Yui’s perspective. She’s been in this village her whole life, and all she knows of the outside world is what travelers tell her."

Sage goes on to say:

Yui gets glimpses of her patient’s lives, but they’re just that: glimpses. Everything else, she has to extrapolate and guess. She’s an unreliable narrator because she, and thus the readers, don’t have the ability to access anything beyond the village borders.

When other POVs are brought in, that same feeling of limitedness and constraint is lost, and that’s a theme I really want to emphasize. Yui can make a difference, but she can’t do as much as she wants to. Her gender, class, location, and occupation all hold her back. One (cough, Madara) could probably make a decent argument for her ideology holding her back, too.

However, I might post outside POVs on [sage-thrasher.tumblr.com] or a separate fic for AUs/other POVs. I haven’t decided which, but I already have ideas and scenes planned.

Worldbuilding

The Naruto timeline is full of vague statements and contradictions, and the farther back in the timeline one is the more sparse and vague the information is. Sanitize takes place before the village is founded and therefore only some very vague information about character deaths could apply; everything else must be constructed wholecloth. Sage briefly elaborated on Yui's personal timeline in 2017:

I might as well take this opportunity to give a vague timeline for each chapter.

Chapter 1: This spans a few years, from when Yui is about 10 years old to her mid teens, around 16 years of age by the end.

Chapter 2: Yui is about 17 at the start, and it covers the span of year, so she’s 18 by the end.

Chapter 3: She’s still 18ish; the chapter covers a few months.

Chapter 4: She’s 19 at the beginning of the chapter and probably 20 by the end, and the chapter spans about half-a-year.

Chapter 5: This chapter has the shortest spread; the first few scenes all happen when she’s 20 within the span of a month or so, and the last one happens maybe a month (or two) after.

I’ve sort of kept the ages/times/dates vague on purpose, and but I’d say say this is all +/- 1 year. I hope this helps contextualize it, though.

What technology is or isn't available in Naruto is also a messy snarl of contradictions and unexplored questions, and backing the timeline up so far to explore a historical time based on the Warring States period is even more complex. Sage explained both her general decisions regarding the technology available to Yui as well as some specific choices:

So, you might be wondering, what’s the technology level in this world? On one hand, there’s crossbows, but there’s also printing presses and ink pens. From what we see with Kishimoto’s work, the technology in that world has not progressed at the same rate in the same areas. No cars/guns, but perhaps trains… yet electricity, TVs, cameras and mass-produced items.

Thus, I’ve taken some liberties. I’m probably not going to include anything after the 1920s, but everything before that is fair game. So, yes, that means there’s technology like electricity and bound books. But, the time period is still feudal-ish; societal structure is definitely that way. Not only that, the technology level is disparate across the elemental nations and within it. Fire, Iron and Lightning might be well-off thanks to their resources, but Sand isn’t. And within Fire, the peasants sure as heck don’t have electricity and fancy things. That’s just for the big cities.

An interesting thing to consider is that travel takes a long time. They go by horse or foot (unless you’re a ninja and travel slightly faster by foot), so even if one area makes a lot of advances, it won’t diffuse and spread to other areas as quickly. I’m going to hold-off a little bit on the telegraph; at the very least, it isn’t going to reach Yui/be relevant to her for some time.

• Crossbows: Yeah, I ended up doing a fair amount of research about this. Canonwise, Kishimoto explicitly excluded guns but was silent about crossbows, so… I took some liberties. They were used extensively in China and were invented there around 4th century BCE. Though crossbows didn’t get much traction in Japan, I’ve based Naruto-verse on a variety of different cultures. Story-wise, I’ve made crossbows somewhat common in Lightning and Earth but rare in Fire. They’ll play a small role in the story, but it won’t be like they’ll go around shooting ninja, haha.
• Stethoscopes: The first stethoscope was invented by a doctor in the 1800s because he was uncomfortable with putting his ear on female patient’s chests. Yup. So he used a rolled-up tube of paper, which worked pretty well, and things spiraled from there. Hence Yui using a thin, carved wooden tube as a makeshift one.
• Bandits and Rounin: I know it’s a trope for bandit attacks, but it’s one that has a fair amount of grounding in history, haha. They’re a pretty documented phenomenon, though it’s not just the “attack-and-rob town” kind but also the “illegitimate toll” kind. The bandits in this one are also rounin, aka rogue samurai, so they have been trained in chakra-use. It makes preying on trade-routes to be even easier. Ninja may be the boogeymen, but rounin are reviled (even if they have good reasons).

Shipping

Regarding ships in Sanitize, Sage said:

I don’t usually answer [questions about shipping] because I have a habit of changing things sometimes; though I have a base outline that I usually stick to, things get rearranged. I wouldn’t want to reveal something and suddenly change it. (Also, I feel like some of the fun is gone if the pairings are revealed, even if it’s not applicable in this case.)

However, based on the multitude of panicked reviews about pairings spurred on by the last chapter, I thought I’d give a clear answer since I’ve basically made up my mind. If you’d rather be spoiler free, do not click keep reading. Thanks again!

There will be no fulfilled romantic relationships between Yui and another character in Sanitize.

The comments on the first chapter — at the end of which Sage asked her readers what their shipping preferences were — seem to lean towards ambivalence on the subject of romance, one fan saying, "I don't mind romance as long as it doesn't overtake anything and as long as it's given reasonable development."

Fan Reactions

A good start!

Sounds like the perfect opportunity for Yui to get some help brewing penicillin - I bet Hashirama would be receptive to the disease theory, too.

I think the story you have is going to be complicated and interesting enough without adding romance on top, but you're the author; write it how you want to.

I really like this. I have a weakness for slice of life fics, especially when the main character isn't a ninja and doesn't fall into the trap of the adventure novel. Yui's quiet competence is really inspiring and I like the natural way her influence has spread, even to Shinobi. That last scene with Hashirama is perfect with its hints of a class divide eroded by exceptional skill and a different philosophical ideology. Looking forward to more.

Oh, this was a good day. Not only an update, but also a promise that the story will expand? Wonderful.

I truly enjoyed how Yui slowly starts changing. If the first chapter was her adapting to this world, this chapter is the one where she actually moves towards improving it. She talks about proliferation of medical knowledge and free medical treatment for everyone, and tries to get better medicine and better tools for it. It's quite impressive, in truth.

Most OC-insert fics have an issue wherein the OC knows something of the world they've been inserted in, and so they try to use that knowledge to make their lot better. Yui is special in that she knows nothing of the Naruto-verse, apparently, and so her adaptation and how she deals with it are far more interesting and novel. The way she dealt with the ninja in this chapter and the previous one were excellent examples of this. Another example is how she speaks like a peasant,despite obviously having been a well-educated woman in her previous life. She doesn't draw on it for anything but medical knowledge, which is unique as well - she suppresses it as much as she can, apparently, because it can't help her.

I don't care much for romance or it comes naturally, it will come. It's clear to me that Yui's primary devotion is and will be to medicine, to healing and helping people. If she finds someone who shares that desire (even if not necessarily in medicine - for example, a ninja like Hashirama, who wants to increase safety and reduce fighting), I feel like there'd be potential there. Otherwise, I have no doubt she'll be fine by herself, with only her friends and family.

It's nice to see Yui's influence expanding, and I can't wait to see how the ninja keep entangling her into their world. Thank you so much for this story.

I really like your style! Yui feels like a realistic mix of past-life and current-life: there is both all this knowledge she has about medicine (which is realistically limited, example: making aspirin) and her being very quiet and down-to-earth which has a distinct peasant quality to it. She feels very three-dimensional :) Actually, all the characters grow little by little with the story, like Sen, so it's easy to get attached to them. Looking forward to the next chapter!

(I also enjoyed your blog little articles explaining technical stuff, thanks for the additional info!)

I love this story so much !

Your narrative is so engaging ; I like how you keep the writing simple and to the point without adding useless info . For example I liked how you didn't waste time on irrelevant stories about Yui's birth , and upbringing like in most OC fics these days . I really appreciate how you included real life information like the acetylsalicylic acid; I don't know you much time you spend researching these facts but it made an incredible difference stating actual facts than just calling them plants. As for the romance I really encourage you to write what you feel , rather than letting readers decide , because this is your creation and while it is nice to please the readers , it could potentially mess up the story if you had a different output about it .

Thank you so much for writing ! Sincerely. I know authors basically get nothing in return for posting fics so thank you for doing so .

I love the attitudes of Madara and Hashirama! Madara is still an asshole without being an evil asshole and Hashirama is still a day dreamer but more mature than the childhood scenes we see in the show.

I particularly liked the scenes at the end where the Yui surprised Madara with the use of the dagger and her interactions about publishing her book. :D I love the idea of people (especially Madara) being surprised by Yui. The fact that Yui in the last chapter doesn't ninja out and fight the Ronan was really awesome too because It really emphasised how separate she is from her alternate universe double (thinking of Kimiko) as well as her single minded focus on protection and healing.

The apprentices' competitiveness was really funny to me, I hope I'll get to read some details about them! (Do they mess up because they're too busy beating each other or is it just making them improve faster? If one is worse at using chakra are they better at something else? Is one of them a better healer/more hard working than the other? Ect.)

I can't wait to see what comes next!

I'm really happy to read another chapter in this story, so long and so well-written.

The hand on the doorstep was and wasn't a surprise. I did expect Madara to kill the rounin and present the ring as a proof of kill, but I didn't expect the whole amputated hand. This is a good testament to the differing mindsets between civilians and shinobi.

It's interesting to note that Yui has become one of the de facto healer of the Uchiha clan. I wonder if Hashirama suspects the identity of her murderous benefactor. I don't think he would ever ask the question directly, but he must be able to make some educated guess.

The scene where Hashirama explodes the healing paste and they both laugh so much was very nice. It makes them more human, more real. They are also growing more familiar to each other. They are encouraging each other to pursue their respective dreams.

And then she met some Inuzuka. She seems to really live in the heart of Fire country, since she is meeting or healing different members of the future clans of Konoha. Would the Nara need her expertise ? Or do they have their own medicines ? Though I think my opinion of this particular clan is now greatly influenced by Vixen Tail's latest story, 108 Earthly Temptations, where they succeed in synthesizing penicillin.

I suspect Toshihiro robbed her of a tidy profit. But, as you indicated it, she is more interested in the dissemination of knowledge than in money.

I will gladly wait for any new chapter.

Thank you very much for sharing this so interesting story with us.

Wow. This is quite well written. It's an interesting take on the Warring Clans era, not only is the SI not a Naruto-know-it-all but, she isn't trying to save the world. She's just trying to as many people as she can. I quite like that.

As for pairings...hrmm. Well, so far, I can see a future for Yui with Hashirama AND Madara, they are both men of character, they care about the person inside and not what's outside.

For Hashirama he's basically found an oasis in the desert in Yui. Hashirama lives in this brutal bloody world and then he meets this woman who saved his brother's life when she had every reason to turn him away, and not just that, but she shares his views, a world where children shouldn't fight wars. He's found his unicorn. And from their interactions so far, a love could easily bloom, they're already finishing each others thoughts. But that would raise a problem with Mito, his future wife, and future jinchuuriki.

And for Madara...well, it depends on whether or not Izuna lives. Because when that fateful day comes, unless they are on the opposite side of the world, Madara is going to take his beloved younger brother to the best healer he knows. He already said she shouldn't undervalue her work, that hints to him holding her skills in high reguard. As to the next question of whether or not Yui can save Izuna? That's up to you.

To why Madara could fall for Yui? He's the type of man who couldn't love someone he didn't respect. As shown already, Yui can be obstinate when it comes to her values, he could respect that. Added to the fact she reminds him of Hashirama, one of the only people that could get through to his thick head. That's a recipe for a budding affection.

But, as I mentioned, it would be much harder to pull off if Izuna dies, more so if Yui can't save him.

As for others? Like a pairing with Izuna or Tobirama? It's wouldn't be in the cards, at least not in this time. They're both quite loyal to their clans, and would probably hold resentment towards Yui for healing their sworn enemies. If such a thing were to be possible, it would have to be after the founding of Konoha. At least that's my opinion.

But I'm not quite sure of the direction of your story. Is it just the story of a healer's life during the Warring Clans Era? Or will she fix things unknowingly by her presense? Creating opportunities for the Senju and Uchiha by being a safe harbor of healing, not violence?

I love this story, can't wait to see where to take this next!

THIS IS AMAZING! You are so SO good at writing my god. I loved the foreshadowing of the last scene, Yui's determination for creating the medicine which was so admirable, the infection conversation (not quite sure why, probably cause I just like the characters, tobirama's a fav of mine :P), oh, and the LAST SCENE. The OUTRAGE. I knew it was coming, but I still have tiny angry tears in my eyes and I kept rereading it almost ten times! I know you're busy with RL and of course that comes first but I very eagerly await your next update!

I was wondering when the conflict would affect her, and how she'd deal with it when a Senju and an Uchiha showed up at the same time, but I wasn't expecting it to make me so emotional. Thank you for writing and sharing another awesome chapter.

this chapter was suuuuch a good one. mostly for two reasons: 1) I think you've done very well setting up yui's circumstances, her short term goals and dreams for the future, and also the people around her. and you've written it so that it's not an information dogpile (as you blend medical knowledge in as well). you write the world building and have created such a good structure for it, it was really awesome to see her little village get a name and for her to realize she had a hand in it. which brings me to point 2) you've fleshed out the world and this world, as our does, has consequences even for the kindest of actions. not everything goes perfectly. we lose things and find things, and people do terrible things even after all the /good/ we've tried to put into the world. this chapter was a good blend of "actions can bring good change" and also "actions can have other dastard consequences". yui can't speculate for these kind of issues and it just goes to show how volatile the world is. I really adore your warring clan era world as you've written.

Ok, wow. I love all the interactions and relationships that she has with all the different characters. I love the details you've put into it and how you've slowly built up her progress over the chapters to where she is now. I like the balance of that while it isn't all positive it definitely isn't all negative either.

I like how you also showed that different ninja could actually be together and stop from attacking each and then the opposite. I like how you've shown her personality and how she reacts to things that she encounters- I like how that when she has the opportunity to strive forward she does.

I like how her patients do care but at the same time they are their own people. Thank you very much for sharing this was brilliantly written. :)

Thank you for another great chapter.

Its stories like these that really make me think. Why doesn't everyone use chakra? Its been established in the lore that you have to have Chakra to live. So why don't construction workers use chakra to mold the elements to make a house? It really is a wasted opportunity in the civilian sector. About the house, this is just another ability that Hashirama can do. Fairly soon, he will be a god. So thanks for not making him a prodigy with medicine.

Like the little details you put in the story. Where Yui was able to tell that Hashirama was sleep depraved and injured from multiple battles because she had so many ninja injuries, she was able to figure out what was wrong with him. Or the part where Madara knocked instead of teleported. Those weren't the only details so thanks for sprinkling them in throughout the chapter.

Like the conversation between Yui and Madara. Madara is all about strength. Telling her to become a ninja and stick up for herself. And while that sounds great, you can't be a great healer and a great warrior. We even saw some of his pride when he said he was clan head. He can also be flabbergasted that kindness can help you. It was kind of funny to see him come to terms that this medic was able to create a contract with a powerful clan. Its these character traits that make them feel like characters. Was surprised that he didn't use the neutral grounds to launch a secret attack against the Senju. Good for him.

Good job on the end scene. Seeing the publisher carry though his end of the bargain. No doubt, he wasn't surprised the book didn't sell in cities. He goes around trading and knows that a woman's name on the title is going to drive off potential customers. It was actually kind of low of him not to mention this to her when they agreed to the terms. After the merchant, it was again surprising to see a minor character from so long ago make a reappearance. How he was the failed doctor of a caravan who thought he was the best only to be beat out by a ten year old girl. Yeah, having your pride hurt that bad must have left an impact. It was only after time that no longer thinking that your great instead SHE is great that doctor Makoto was able to see the truth. This makes so much sense! It was the ending that made me so sad and happy. We saw constantly that Yui only cared about helping people, almost never about herself. Yet to see her get no credit and only half the rewards for her accomplishments is hard for us readers. Sadly, this has happened in history where famous inventors, artists, doctors, etc. aren't given the credit they deserve until years after their accomplishment. She will be lucky if people even know in the future that it was her accomplishment.

This was so GREAT! I'm glad that Hashirama was able to regrow/rebuild her clinic, and that she used her influence to get them to formally agree to the village being neutral ground. Madara's certainty that Hashirama's dad would never agree was perfect, and I loved how Yui didn't even say anything, just gave him the scroll. I do hope she makes sure to mention it to all the other ninja she treats as well - surely other clans have grudges as well?

Oh my goodness I'm so glad she's getting instruction from someone educate. Knowing the proper terms will make her sound so much better. I'm also real glad she didn't take any shit from that merchant - I bet his attempt at weaseling out of the contract terms didn't do anything good to his reputation with his bodyguards.

Really really great chapter, and I can't wait to see what happens next in Ninja Politics. A neutral ground that everybody respects is a Big Deal.

This is, by far, one of the more realistic OC's I've read. Not like that Mary Sue crap I come across in the Naruto fandom — they're fucking riddled with it! And it's all about romance!

Anyway, just wanted to say your Yui is awesome and she's right up there with Silver Queen's Shikako because it's good to see awesome female leads!

Wow. You managed to make hashrama to be so human. Like even HE is selfish and not messiah-like by most fanfiction. And madara asking her questions he probably won't be able to asked anyone else and the fact that he's considering peace. And hashrama panic on hearing marriage is a little hilarious. So tobirama and mito huh? Most of all, I really really love the fact that you can make things so realistic and so human.

Wow. No, really. Just. Wow. I was a little put off when the fic started with little information on the character,but the writing was great so I stayed. I didn't expect to be taken on a ride that literally warmed my heart! You've done so many things right with this fic. I particularly love that the character has knowledge of her past life but not of her new one. Seeing her adapt throughout the years is extremely pleasing and satisfying- and I mean it. Yui is such a real, believeable character and I'm in love with her! It's interesting to see the thoughts of someone who was shaped by ideas of freedom and democracy and by an age of knowledge work their way through a completely different culture and time period, not to mention how cool it is to see those ideas start to spread, if slowly, due to her influence. I also love the effects and role she's having on the characters- especially Madera. I know you said romance won't be the focus of this fic- which I appreciate - but personally, I gotta say I particularly love Yui and Madaras interactions. They're so dynamic and if they ever become more comfortable around each other, I could definitely see a very cute relationship dynamic. Like a Madara who has a hard time coming to terms with his feelings, and an oblivious Yui. I'm already picturing cute scenes in my head- like a smaller Yui sitting comfortably in a stoic, oversized Uchihas lap while she grinds herbs, or one of those cliche 'guy pins girl to wall' scenes (im a sucker for those) or a confession scene that mostly involved a flustered Madara begrudgingly admitting his feelings and a blunt Yui just being like "oh. Okay." I know I got a little off track but I have... So many cute ideas for those two but I don't want to bother you too much with them. So. Yeah. Again, amazing fanfic! I know you updated recently but.. I'm gonna be waiting for the next one and cheering you on!

You've done an amazing job in writing up this chapter! I love the subtlety with which you handle canon context, not to mention the effortless world-building.

Your characters are organic and feel true-to-life; Yui in particular. :D I get the feeling Hashirama does have feelings for her, but at the same time he's bound by familial obligation/personal ambition. In the latter case, I figured his marriage with Uzumaki Mito would put a stopper on things but - in light of Tobirama's (non-canon) wedding - this may be null and void. I'm not usually a shipper but Yui/Hashi would be sO CUTE, GOOD LORDY. Like, this chapter was already cute, but i'm talking astronomical levels of sugar with a generous dollop of Yui being amusingly thick, and stubborn as nails if the relationship threatened to overtake her chief profession. However Yui's personal plot turns out, I'd be content with her living out a happy ending (pretty please).

Madara is so awkward it's amazing? And a little scary because secondary embarrassment is big thing. :') I hope he takes Yui's words to heart in securing a peaceful future.

Sen and Eiji got their asses whipped, though I feel it was well-deserved and then some. What use is teaching if your students are going to run in the general direction of death? On the other hand, their opinions are understandable - human. Have I mentioned how much I enjoy your characterisation?

Rambling aside, I'll be looking forward to your next update! And thank you for investing time and effort into Sanitize, as always.

-Van

This is the second fic I've read of yours...but I'm already adding you to my alert/fav list. You've got serious talent at writing such a well-paced story. You're not rush it...you're showing how Yui is changing the world without just "telling" the reader. I love seeing how Yui deals with the problems that some SI/OC fics don't touch too much on (the sexism being one of the major ones...I like that she understands how unfair it all is but will conform to help as many as she can). The nature of letting everyone learn about chakra is interesting...I'm sure there can be a middle ground (kind of how like now doctors/nurses have to obtain a license to practice medicine and whatnot...maybe a similar restriction could be introduced in the far future of Yui's world for doctors that want to utilize chakra without having to become shinobi).

While this is listed as a drama, I can't help wonder at the possible romance pairings now that it looks like Tobirama is engaged and not Hashirama...his reaction when he thought Yui was getting married was hella cute. There's also Madara who may be interested...though, I don't enjoy love triangles because there's always a person that loses out and I kind of like Hashirama and Madara equally. Either way, your story is engaging without any focus of romance...I could probably read a lot more chapters with Yui revolutionizing the shinobi world while being completely blind to any romantic plans that Hashirama and/or Madara may have on her. Probably would be more amusing, tbh.

Ahhh, what an amazing story. I'm really loving this so far. Also, if you're still taking suggestions on the eventual romance then I would probably have to say Madara. Him and Yui just have a very interesting relationship. She challenges the way he thinks and he has this bregudging respect for her. Her cool temperament is also a nice contrast to his more fiery one lmao. I don't know, I guess I just really like the ease of their relashionship. I can see it working well. Hashirama, on other hand, strikes me more of a platonic soulmate to Yui. They have similar visions for peace and they bring out ambitions for better in each other because they're such kinder spirits. Honestly, just well done on all the relashionships in this fic, they're marvellous and layered.

Also thank you for adding little details that make this fic so unique. Medical knowledge (I imagine that took some research unless you have some medical training yourself), the sexism in this type of society, and even Yui not knowing how to fully read. They're all really nice touches!

Thank you so much for writing this. Can't wait to see where this goes next.

I really like the story, I’m so glad that I found this story. The story is well written, the character developments are good, the storyline is interesting and realistic. The main character is interesting and isn’t that much of a Mary Sue. So thank you for coming up and writing such an incredible story!

What a chapter! We got more Hashi/Yui bonding, Tobirama being his awkward turtle (I'd really like to see Yui from his POV, or even from Madara or Hashi's POV), and Izuna starting his journey of enlightenment (hopefully).

I liked seeing the treaty in place and how Uchihas/Senjus still hate each others guts but respect it. Izuna also showed the perspective of maybe lower clan members who don't get the big fuss over Yui and see her as an opportunist.

Thanks for the update!

At first, I was a little skeptical to read an OC-insert story, since they aren't typically my cup of tea. But the premise was interesting, and there are so few stories set during the Warring Clans Era, so I decided to give it a go.

...And I was hooked! Your writing is amazing. Your characterization of Madara and Hashirama are exactly how I imagine them, and you're amazing at setting the right tone for different interactions. And every single scene is relevant, has a role to play, and contributes to the plot in a way that doesn't make it seem forced. Yui is also a likeable OC, someone who isn't overpowered, liked by everyone, or always making the right decisions, but has strong beliefs and determination. The plot itself is also very unique and has a lot of potential to go places.

Thanks for writing this, definitely favourited and followed! (Now, to go check out your tumblr content and other fics.)

This chapter hit me like a train. I want to write some kind of insightful review but honestly I'm still in shock. As always, it was a pleasure to read and I wait with bated breath for the next chapter. The journey so far has been one of the best, and this fic is definitely one of my favourites. All your characters are fantastic people I've grown to genuinely care about. It was for that reason I will genuinely miss Sen. You created a real person with ambitions and interests, and a personality I rather liked; it was heart-breaking to see that all taken away. Essentially, you did your job extremely well! Yui is a wonderfully compelling character who feels so incredibly real that my eyes prick with tears whenever hardship befalls her and furthermore, reading about her road penicillin was so engaging that I was hoping with all my heart she would figure it out and when she was finally successful I felt like I myself had just won something. There's so much more I want to say about her but I can't quite put it into words. You and your wonderful betas have done an excellent job. Keep on keeping on!

Like the combination with real medicine mixed with chakra magic. The part with using sealing scrolls to kill bacteria was quite creative.

Its nice that Yui gets out of the lab every once in a while to enjoy the small pleasures of the world. Spending time with her sister, playing with her neice, gossoping. Their all great ways to show that the world doesn't revolve around just one profession.

Thanks for sticking to her character when she shared her discoveries with the doctor. She doesn't have the family heritage to provide her with credibility to feudal lords. So she continues to give discoveries to him while asking for small rewards in return. She also isn't naieve. She didn't invent biotics. So it would be wrong for her to take all the credit.

The death of Sen really got to me. You had him built up over the story and now with him dead, it really feels impactful. The story actually got me to feel something. Also the complexity of what his death means. Most other stories would have had the hero fail because he/she couldn't save the person in danger. Yet Yui does know how she could have saved her brother just didn't have all the 21st century medicine. Could she have saved him had she worked harder? Its impossible to know and really gets you thinking on what could have been.

Now this is an example of an SI/OC kind of character done right.

Yui's knowledge of modern/real world medicine informs her character and gives her some interesting perspectives on the ninja world, but she's not constantly pining for a world she can't go back to or making awkward pop culture references. She's in that world and making the most of it. I liked her musing on penicillin and how difficult it would be to make in a society with that level of technology.

Most of all, I love how well she plays off of the canon characters. She feels like she belongs. The scene with Madara really stands out as he bristles at the notion that all ninjas are mindless killers who love only money. Who's been keeping the roads safe? Is it evil to do your job in a time of war? And then leaving the severed hand on her doorstep with a note saying the debt has been paid - so perfectly Madara.

This has been a pleasant surprise.

Okay. I'm still loving the story, but I honestly don't know where you're going with it. Well, I never knew where you were going with it, but now that you've shaken up the status quo with the last two chapters it seems more relevant to wonder.

I don't really know what to think of Lady Fukuyuma. But, I thought the shock at the suggestion of Lady Hisayo nursing her own child was a wonderful and subtle use of the cultural gap between Yui and the world she resides in. It's not as bad as it would be if she had just been dropped in the world as a fully formed adult, but this chapter has highlighted how growing up in a rural nothing town and becoming influential enough to have her "eccentricities" forgiven has done her no favors in in that regard. That said, she's unlikely to mess-up enough that she'd ever be in real trouble.

It would be interesting to see how Yui's connections to the leadership of the slowly forming Senju-Uchiha alliance will impact her relationship with nobility. Because while nobility has power, they only have it because of the shinobi/samurai power base. So while they can make her life difficult there is a certain point beyond which said shinobi may decide that tolerating harassment of hers is more of a hassle than the potential consequences of pro-bono wetwork. And someone like Fukuyama must be aware of that, considering how he seems to know of her from his shinobi employees.

After all, while he may've been protected from Senju or Uchiha assassins by the other clan (whoever he employs), if he angers both he'll lose that protection. And if he employs Uchiha, which I assume is the case considering his statement about Senju healers, that would mean it is much easier for him to anger them by mistreating Yui. Because of just how much more valuable she is for them compared to Senju.

Overall, great story so far. Good premise, great execution.

Further Reading

• The Ninja of Sanitize — More info about the ninja OCs.
• Sanitize, starred reviews on Ficdb