This story started life as a Pat reon commission, but enough chapters have been commissioned to justify its own story. All credit to my generous patrons Hangwind and Akitsu91.
Disclaimer: I own neither Youjo Senki nor Naruto
Shoulder Devil Ch. 1
Konohagakure law officially classified the Haruno family as civilian, but that did not mean they had never produced any shinobi for Konoha. In fact, it was not at all unusual for civilian families to send a second or third son into Konoha's shinobi forces. They rarely achieved high rank, but when the village's chief export was chakra-powered mercenaries, having one in your own family was seen as being socially responsible, patriotic, and even fashionable. Kizashi Haruno himself had been a second son who had done five years as a genin, survived the Second Shinobi War by virtue of never facing an enemy shinobi without more powerful allies, and then quietly retired and used his aura as a war veteran to marry well and set up a successful merchant business.
When birth complications left his wife unable to bear a second child, both he and his wife had assumed their darling daughter Sakura would grow up to either marry well by virtue of being his sole heiress, or perhaps do the daring thing and take over the business. Then when she was almost six, Sakura had to go and declare her intent to become a shinobi.
His wife Mebuki thought being a kunoichi was an uncivilized path for a lady of breeding. Kizashi had far more solid reasons for refusing. He remembered his own days as a shinobi well enough to know it was no life to wish on his daughter. The lunatics who specialized in combat operations rarely lived to see thirty. The more sane shinobi who spent most of their time in non-combat roles had careers that were long, tedious, and underpaid - until something like a war forced them into combat where they would then be summarily butchered by enemy combat specialists. And that's leaving out things like tailed beast attacks. Bad as the civilian casualties had been, that was nothing compared to the shinobi who had been stuck trying to fight the nine-tailed demon fox.
Unfortunately, refusal had not been an option. Their daughter had somehow made friends with the heiress to the Yamanaka Clan, and she had made her declaration right in front of said heiress. While refusing to let her attend the ninja academy was still within their rights, it would have been social suicide. When the daughter of a major shinobi clan head tells you she was looking forward to seeing your daughter at the academy, you let your daughter attend the academy. The excommunication and suicide of Sakumo Hatake was still held as an example of what awaited those who tried to swim against the cultural tide.
In privacy, his wife did everything possible to persuade their daughter away from her course. When that didn't work, she entered a state of denial where she convinced herself her daughter was simply going through a phase she would grow out of. Kizashi was more pragmatic, and focused on doing what he could to maximize his daughter's chances of survival. Unfortunately, the nature of his far flung business meant he could never give his daughter the personal attention and benefit of his own experience. He did his best, encouraging her to study every theoretical aspect of shinobi work and purchasing all the necessary books in the hopes that she might be tapped for a non-combat role right out of the academy. And in his quest to give his daughter every advantage, he came across what he thought was a very useful little toy.
It was on a trip to Sunagakure that he came across the jeweled brooch in the market. It was a large semi-precious stone set in a casing composed of ridiculously intricate clockwork. It was apparently a curio obtained from the strange lands far to the west of the Great Desert. The merchant who possessed it could mold a bit of chakra, and he used this to demonstrate how the clockwork would spin and move in dizzying patterns when exposed to chakra. Kizashi immediately recognized it as an excellent tool for encouraging his daughter to work on her chakra control. As such, he did not hesitate to spend his entire profit margin for the trip on acquiring it.
Sakura Haruno loved her new toy. She did not reveal it to anyone because it felt so childish, but in private moments she loved watching the intricate movements of the clockwork. She was also a very bright child, so it took less than a month for her to figure out that the number of gears that would move depended entirely on the pattern in which she entered her chakra into the device. It became a game for her to try and enter her chakra in a way to create the most complicated movements. Then she realized that the device had gears that were not only invisible, but didn't actually exist. Enter chakra in just the right way, and she'd feel gears start to move in her very soul.
Sakura was hooked. What started as a game became a minor obsession. She didn't realize it, but trying to divine the device's secrets pushed both her chakra capacity and control to far beyond normal levels.
It was shortly after her ninth birthday that she found a very complex pattern that moved every single gear.
"It has been so long. Who are you?... Ah. I see. You are the holder of my prison."
"Prison? You are trapped here? Who are you?"
"Trapped. Yes. After I died, my soul was trapped in this infernal device. As for me, I had many names while I lived. Some called me Shining Silver. Others called me The Devil. But you can call me Tanya."
Sakura was at heart a kind girl. Her first instinct was to be sad that Tanya was trapped in the brooch, which was apparently called the Type 95, whatever that meant. Once it became clear that even if she could free Tanya it would mean her soul would simply disappear into the afterlife, she got used to having the little voice on her shoulder. Tanya, Sakura realized, was not a very nice person. But she had a wonderfully dry wit that made her laugh even as she felt guilty for all the mean things Tanya said.
Tanya was also encouraged her to study and train hard. In fact, Tanya was absolutely brutal. Once she understood what being a shinobi meant, Tanya drove Sakura to train and work to levels that Sakura thought insane. But unless Sakura wanted to leave her newfound friend behind, she had no choice but to do at least some (most) of what Tanya required of her in order to keep the peace between them.
You really think I can help free you one day?
Yes. It is clear that your people have developed magical abilities - yes, yes, I know you call it chakra - far beyond what my own people ever achieved. There might even be a method to create a body that my soul can be transferred to. But I doubt it's going to be easy. Which is why you need to be the best shinobi you can be.
So you are helping me just for that?
Of course. Understand Sakura, true friendship and loyalty takes years of effort to build. I had friends like that, but it came to pass only after we had gone through years of hell side by side. In time, we may become friends like that. Until then, the only trust we have is our desire for a common goal. You want to be a great shinobi. Creating a body for me will most likely require a great shinobi. Thus, our goals align for now, which is why we can trust each other.
However, Tanya acted as more than a drill instructor in her head. While she acknowledged her own powers were far less flexible than what chakra could offer, she mentioned one thing that set fire to Sakura's imagination. In her past life, Tanya could fly.
The only shinobi that Sakura could think of who was known to fly was the current Tsuchikage. Even a month of research only turned up mention of a Land of the Sky, but their ability to fly must not have been very good, Tanya pointed out, because they were wiped out during the Second Shinobi War.
Attempts to fly using the Type 95 met with failure. After many trials, they both concluded that the jewel's power was almost entirely tied up in keeping Tanya's soul prisoner.
Still, even though it could no longer be used to fly, the Type 95 did allow Sakura enough power to perform a few useful tricks. Physical reinforcement and reflex enhancement, the basic spells from Tanya's life, and the basic abilities of any shinobi. With Tanya's help, Sakura learned how to enhance herself to match any of the clan ninja in her class.
It wasn't all fun and games though. There were some serious arguments. Particularly when around the age of 10 Sakura developed her first crush.
"Sakura, you will go back tomorrow and apologize to Ino! And you will make it convincing! I can't believe you're throwing away a friendship like that over some pouty brat!"
"He is not a brat! Sasuke is the coolest most awesome guy in class! He's the last Uchiha! He's a super-talented ninja! His story is so tragic... he's like a prince from some great saga!"
"The only tragedy I see here is you throwing away an alliance with the heiress of a great shinobi clan in order to chase after damaged goods."
"SASUKE IS NOT DAMAGED GOODS!"
That was the first time Sakura had willingly thrown away the device from herself, sending it clattering to a corner of her room. For a full week the only attention she paid it was to throw it the occasional glare. However, since she had also broken ties with her closest friend in the physical world, it wasn't long before the loneliness got too much to bear. Finally, Sakura swallowed her pride and took up the Type 95 once more.
"Tanya? Are you there? I'm sorry for shouting at you."
"You were upset. I forgive you. Perhaps my own words were rather harsh."
"So you don't really think Sasuke is damaged goods?"
"Sakura, think about it for a minute. The boy's entire extended family got murdered when he was eight. It would be unbelievable if the boy wasn't mentally damaged. I lived and fought through a war, Sakura. I've seen trained adults break with only a fraction of the loss Sasuke suffered. And no amount of sympathy will change this fact."
"Well then it's even more important for me to get close to him! Love will help him heal from his loss!"
A groan echoed out in Sakura's mind. "Sakura, love isn't some kind of bandage you slap on a wound and just wait for it to make things better! Besides, my people had a saying - love is a two-way street. It doesn't matter how much you love him, it's completely useless if he doesn't love you back."
"Well that just makes it even more important for me to get close to him! Then he will realize his love for me!"
"Just like you've realized your love for Naruto?"
"W-WHAT?! Ewww! Why would you say that? I thought you hated Naruto!"
"I do. Which is why you can imagine my disappointment to see you acting like him. Trying to force your attention on poor Sasuke with no respect for his feelings..."
"But... but then how can I make him love me if I don't capture his attention?!"
"You're really hung up on this brat, aren't you?"
"Alright, alright, I suppose Sasuke is still rich even with his clan dead, so pursuing him isn't a total waste of time..."
"I don't care about that... wait does this mean you approve?"
"No, I don't. But I will make you a deal. You make up with Ino, and I'll help you draw Sasuke's attention."
"Wait, why should I make up with Ino-pig when she's my love rival!"
"Sakura, this is non-negotiable. Ino is the heiress to a major clan. And unlike the Uchiha, her clan is still alive. So if she decides to ever get serious about your little rivalry, she can create all sorts of problems, not just for you, but your future career, and maybe even your family. How hard would it be for a clan of information specialists to spread a few rumors wrecking your father's business reputation? Or for the head of the Yamanaka to arrange for one pink-haired genin to be assigned to permanent sewer-cleaning duty?"
"Ino wouldn't do something like that!"
"Perhaps not right now when she's too young to think of such things. But as she grows older and starts wielding actual influence? And the worst part is, even if you succeed in capturing the Uchiha's heart, he won't be able to protect you. Not without a clan of his own."
"So what do I do?"
"As the first step, you will apologize and reaffirm your friendship with Ino. It's only been a few days, it shouldn't be hard at all you retake your old position as her best friend. And you will be her best friend. You will support her in all endeavors, you will sympathize with all setbacks, you will become her closest confidante. You will be such good friends that when the day comes and you steal Sasuke Uchiha out from under her, she will be too busy being happy for you to feel jealous."
"Um... that doesn't sound very nice..."
"Why? It's not as if you'll be lying to her. You really will stop chasing the Uchiha. Hell, if she asks, you'll even help her with her own attempts on him."
"Because, Sakura, the real trick isn't getting the Uchiha. The real trick will be surviving the backlash from all the others looking to get their hooks into him. And the way to do that is to get Sasuke to come to you."
"It's simple. Chasing Sasuke will make you enemies you can't afford. But if Sasuke is the one chasing you, then your friendship with Ino will mean she will be more inclined to help rather than hinder. Particularly if you appeal to her pride by turning to her for advice when it happens. If you play it right, Ino will not only help you, she will think it's all her own idea. But for any of that to work, Sasuke will have to approach you entirely of his own volition."
"But how do I get him to do that? He never seems to pay attention to anyone!"
"The same way any business goes about marketing a product. First, you need to research your customer, and determine his utility and preferences. Then you need to customize the product according to demand."
"So... I need to spy on Sasuke?"
"What part of 'you need to stop chasing him' did you not get? No, what you need to do is study the Uchiha clan."
"Why the clan?"
"Because, Sakura, members of prestigious shinobi clans marry not for love, but politics and genetics. Sasuke was eight when the Uchiha died, which means he was old enough to have picked up on their ideals and prejudices. You want to attract the last Uchiha? You need to find out what the Uchiha usually looked for in their spouses. Most of the really juicy info will be locked away in private records, but given how famous the Uchiha were, there should be some useful stuff available in public."
"So... the library?"
"No. First Ino. Then the library. And maybe the village records offices. This is not going to be quick, Sakura. But information gathering and patience are both important skills for a shinobi to learn."
Sakura thought about it for several minutes. Although it seemed sketchy, she realized Tanya was right. As long as she was a good friend to Ino and never actually tried to do anything behind her back, then it was perfectly fine. Turning herself into Sasuke's dream woman, she'd be doing it right in front of Ino, so was it her fault if Ino didn't notice? And Tanya had a point, even if things didn't work out with Sasuke, at least she'd still be best friends with the heiress of a major clan.
Thus decided, Sakura headed out. She had a best friend to make up with.