This is my take on the challenge based on the oneshot Kyuubi's Plan by Sage of FanFiction.
I would just like to say I do not own Naruto or any of the other things I pay homage too. If you like one of my ideas please, feel free to use them in your own stories, though I would appreciate a PM so I can read them.
Uzumaki Naruto was having a rather unusual week. On the first day Yamanaka Ino, hoping to impress the class heartthrob Uchiha Sasuke, attempted to show off a jutsu that she had invented herself based on her clan techniques which was of course completely untested. This ended with everyone falling unconscious for an hour and waking up with a migraine headache. Well almost everyone, as the spoiled rotten village golden boy Sasuke didn't wake up which almost got Ino executed by the civilian council.
After that as the days went by and Naruto found himself changing a little bit both mentally and physically each day.
Physically after only a week he had gained several inches of height making him taller than what Sasuke had been the last time he had seen him, he had gained a good deal more muscle on his bones, his hair had grown in length down to his shoulders as well as sprouting thickly on his chest and nether region, and his eyes were now slit like a cat… or perhaps a fox. He had noted when he had cut himself with a kunai while training that he now healed at a visibly accelerated rate. His senses had been enhanced quite a bit allowing him to see hear and even smell things he never had before, which lead to a sudden need to clean his apartment very thoroughly to get rid of some of the odors that permeated it. This also, he found, gave him better reflexes as with the enhanced senses he became aware of things much sooner and could react accordingly. He had even become very chakra sensitive it seemed as he had been having these strange sensations that when he had asked Iruka sensei about them had received an explanation of how chakra sensors like himself could track people by their chakra with proper training. He had also found out that this was how Iruka could always find him after a prank or when he was cutting class. Finally when he had showered he had found that his 'male' parts had also grown in length and thickness a good deal.
The most startling change for him though had been the mental changes. They seemed so drastic that he almost wandered if that jutsu had changed him so fundamentally that he could really be considered the same Naruto anymore. Most notable was that he no longer found any interest in Sakura. Her screeching voice hurt his enhanced ears and the first time she had attempted to strike him his new reflexes kicked in forcing him to counter with a grapple that had dislocated her arm leaving her out of class for three days. He also found it much easier to remain calm and focused on things that before he had found boring, like Iruka sensei's lectures, and that he could understand and remember them too. He found that his instincts were also enhanced leaving him suddenly leery of Mizuki sensei though he was uncertain why. And finally he found that what before he had considered perverted and thus wrong now intrigued him. This lead to the thought that, with the enhancement to his aforementioned 'male' parts and his near limitless stamina which had in fact also grown, he would be a real lady pleaser in the bedroom. Perhaps, if he could convince them, he would even be able to pleasure multiple girls making them very happy.
His wallet was also much lighter since during his growth spurt he was noticeably hungrier and his old orange jumpsuit had grown far too tight for him. He had gone from store to store until he had found a shinobi owned one by the name of Wolf's Claw where his new instincts were not instantly warning him off. He had then gotten a full wardrobe of a dozen black just beyond knee length shorts and white sleeveless shirts with a pair of black jackets sporting the red spiral on the back for the price that two of those jumpsuits had cost him. He made note to give this shop his business from now on, especially if the friendly kunoichi with the twin buns in her hair remains working there.
However something in the way the teachers were acting today made Naruto feel that for some reason today is going to bring the biggest change yet.
"Alright class, listen up," Iruka called out getting everyone's attention.
"As you all know Sasuke has been in the hospital since the incident last week. Well Sasuke has finally been released however has undergone some err… changes that will be explained soon," Iruka said as the door to the classroom opened and someone entered.
It was a girl with raven hair that went down to her hips, black eyes, and skin that was somewhat pale like she hasn't been out in the sun all that much.
All in all she was very beautiful which most of the boys in the class made known, most noticeably Kiba who stated that she was "a fine looking bitch". This in particular earned an angry scowl from the girl though she didn't seemed pleased by the reactions of the others either.
Naruto's eyes opened wide at that, 'No way! It can't be' he thought when he saw that look on her face, but as he looked closer he saw that despite how different they looked there are a few things that are either completely the same or at the least very similar.
"You got to be shitting me! Sasuke is that you?" Naruto called out loudly, the entire class froze at that.
"(sighs) Figures that you are the only who could tell… dobe," the now identified Uchiha said. The class then erupted into a screaming mass with questions of what happened and wails of how it can't be true. Iruka used his demon-head jutsu to quiet them all once again.
"Now then I know you all have questions but if you all wait I'm sure Sasuke will explain," Iruka told them before nodding to the Uchiha.
"First of all my name is Sasumi from now on and as for how I'm a girl, well… it turns out that I've ALWAYS been a girl. However since my father only wanted male heirs he had seals placed on me when I was born to make me appear to be one. The reason why that has changed now is that one of the seals affected my mind so I would think like a boy. That seal was broken when Ino used her jutsu and since all the seals were connected the others started to fail as well which is why I spent a week at hospital getting used to the new me," Sasumi explained to the class who just sat there with looks of disbelief.
Iruka then snapped them out of it. "Okay now that explanations are done please sit down so we may continue," he said after which Sasumi went and took her normal place next to Naruto.
"I had a strange feeling that today was going to be different but this was completely unexpected Sasu-mi," Naruto told her.
"How do you think I feel about all of this? My whole life turned out to be a lie, it's like I'm a new person entirely," She said in a depressed tone. She then turned and looked Naruto in the eyes.
"Naruto?" She asked.
"Yeah," he answered.
"Do you think we could start over, I mean we didn't get along very well before but since I'm in a way a new person starting a new life maybe we could get along and even be friends this time, especially since your apparently to only one except Hinata who hasn't lost the ability to speak due to my new gender," Sasumi asked him.
Naruto was surprised at the request since the Sasuke he knew would never consider having a friend let alone actually ask someone to be his friend… but then that's just it, this isn't the Sasuke he knew but a girl named Sasumi so why not, and with that Naruto gave her a smile.
"Sure I wanted to be you friend before but you believed you didn't need any then however you're apparently much nicer now," Naruto answered making her smile, then Naruto recalled something.
"Hey didn't you say that besides me Hinata was not shocked by the new you," Naruto asked as he looked were Hinata was sitting who when she saw Naruto looking at her blushed and waved a bit and then fainted when he waved back.
"Yeah I asked for Hinata to help me with the whole being female thing since she is someone I recognize and she is a girl in my class but not one of my (shivers) fangirls. We got along pretty well, especially after I managed to get her out of her shell a bit. In fact I guess we are friends now," Sasumi answered.
''Really? Then maybe the three of us could train together or something sometimes," Naruto asked hopefully at the thought of getting another friend.
It was at that moment the bell rung signaling that the academy had ended for the day. Sasumi gave Naruto a nod before leaving.
When Sasumi got home she removed her sandals and most of her cloths leaving her in just her underwear before she lay down in her bed with a sigh after which a smirk made its way onto her face and her eyes flashed red.
But it wasn't the sharingan. No for that split second her eyes were blood red with slit pupils, the eyes of the Kyubi.
The demon fox now called Sasumi thanked Inari for the incredible luck she had.
She was sure that when the Shingami locked he into Naruto that she would stuck there in that disgusting sewer until the boys short human lifespan ran out and she an immortal demon would die along with him.
But then that female mind-walker used that jutsu of hers connecting everyone in the classes minds including hers and gave Sasumi a way out, something that she took almost instantly. The only reason it wasn't instant was that she realized she needed a moment to think through everything and to make some plans. So she used the mind link to knock them all out without breaking the connection.
After that she started to analyze her situation taking advantage of the fact that time moves differently in the mind.
First of all even if she left the seal her soul is still tied to Naruto's. Second even if it wasn't she would still die once whoever's body she took died from either old age or something else like getting killed since she would only being able to bring about half a tails worth of chakra with her without risking destroying the body and that wouldn't be enough to make the body ageless.
Yeah rushing things would end badly.
Luckily for her she found a way to live outside, not die of old age, and not be powerless but also even better a way to gain company that won't die from old age while also getting back a Madara since she choose the Uchiha's body so she would have the sharingan after changing it to fit her and consuming Sasuke's soul.
Due to being able to get around the seal but still being connected to it she could now change it a bit, so she made some improvements.
Oh yes once she was done Naruto would be far above everybody else.
She altered the seal so that more chakra would be sent into Naruto, that chakra would then improve him in several ways most importantly turning him into a half-demon… well two-thirds demon anyway as the quantity would far exceed and overpower his human side. While also leaving behind on his back a false 'broken' seal that would have disabled the boy both mentally and physically while also sealing any bloodlines he might have had if it had ever truly been active. Let the old man Hokage puzzle over that one trying to figure out who had done it to his effectively adopted grandson. She was sure the finger would get pointed at one of the elders or Uchiha as they had always been against allowing the boy to live free and not turning him into a living weapon. It was much like the fake 'broken' seal she had placed on her own new body that would have transformed its gender and mentality while forcing production of testosterone which would account for her decided lack of Sasuke's former aggression.
The alterations to his seal though would give him a body far superior to that of a normal human's that would stop aging at around the age of twenty when he reaches his prime. Some of the chakra was set to activate two of Naruto's genes unlocking the Uzumaki's special chakra and the Senju's mokuton, though she was curious how his natural high wind affinity would affect that. Finally it would give him four new forms using his surprisingly high aptitude in transformative techniques that she assumed he received from exposure to her chakra while in the womb as demon chakra while destructive can also cause mutation leading to the birth of bloodlines.
The forms would be human, half-fox, were-fox, and full fox though the more advanced forms might be locked away until they could get ahold of the key to loosen the seal so that he can access the fullness of her former chakra.
The human form is just that, human. Besides the whisker marks he had already had and the now slit eyes he looks completely human and this form would replace his old one. It also included enhanced physique, mental capabilities, and senses including the fact that she had opened his third eye wide open giving him a strong awareness of chakra. Her constant presence had forced his third eye almost completely closed, as it would be like starring into the sun with the amount of chakra she had contained but now that chakra would be his and his third eye would adapt. In this form he could access at max one full tail worth of her former chakra as the body had limits on how much it could channel.
The half-fox form would give him claws, orange highlights in his hair, fox ears on top of his head instead of human ones, and three fox tails. His enhanced physique and senses would be magnified in this form and he would have access to up to three tails of her former power.
His were-fox form would look like a bipedal male kyubi with six tails that would be somewhat taller and larger than his human or half-fox forms, perhaps twenty-five percent bigger in fact. Also his enhanced physique and senses would be further magnified while still allowing the use of hand signs in this form. Finally he would be able to access a full six tails of her former chakra.
The full fox form would then turn him into a male kyubi the same size as her original form with the corresponding enhancement to all his physical abilities though this would come at the cost of not being able to use hand signs in this form. Much like she had he would be restricted to raw chakra shape and element manipulation though he would have the full eight and a half tails worth of raw power to use. Fortunately his special chakra would probably render this point pretty much moot anyway.
But most importantly to her though, due to Naruto's new demonic side he can now place mate marks on those he chooses turning them into half-demons as well with improved and ageless bodies.
Sasumi licked her lips at the thought. Sure it would take a long time before she became as powerful as she once was, she might in fact never reach that level of power again, but still she knows that at the very least she'll be able to reach six or seven tails of power and the rest she'll be able to make up for using human jutsu and the like since from what she had heard at one point while she was sealed in Kushina, the human known as the third Raikage had fought the Hachibi to a draw.
Best of all she will have someone to spend her life with. Naruto still has eight and a half tails of her chakra. Add the power of the Senju and Uzumaki as well as what he will gain with training and he will be an excellent mate for her far exceeding her previous power level.
Hmm it might be a good idea to add Hinata to her little family as well. With Naruto's stamina he could easily handle both of them and this way she wouldn't have to fight her for Naruto's attention. After she is convinced to share him, unlike many other girls, she won't care about who is alpha female as long as she can be with Naruto.
Sasumi giggled at the thoughts running around in her head. Yes everything would be perfect. She would be free with two who will love her whom both, once pushed in the right direction, would be powerhouses and the three of them would be together forever.
And as a half-demon Madara's eyes will no longer work on her like they did before especially since she also has the sharingan now with hers being empowered by her half-demon status to no longer need murder to enhance it instead being trainable beyond the normal max. Similar things will most likely happen to Hinata's Byakkugan and Naruto's Mokuton and Special Chakra.
"Oh the fun we will have," Sasumi moans out before getting up and heading for the shower since she will need to cool down and to change into a new pair of panties now.
After that she'll work on how to get on the same team as Hinata and Naruto so she can more easily help push them to become stronger as well as strengthen the relationship between all three of them.
She'll most likely ask the Hokage to put them together by telling him that they are the only ones she is comfortable around due to how easily they accepted that she is female now.
Yes that will work, now all she needs is to wait two weeks until graduation day to be with her mates. By then Naruto's transformation should be coming to its' finalization. He will receive the little message she had left behind and know of the great power she had given him.
AN: I read this story, (Kyuubi's Plan by Sage of FanFiction) and just couldn't resist writing the challenge as I have been thinking of doing a Mokuton Naruto for a while now. As you can see I have made some slight changes in how the first chapter is written but only to give it my own flair. Don't worry about my other stories as nothing is abandoned or anything, it's just that I write what my muse gives me and right now she wants me to work on a mokuton story. I hope you enjoy my version and continue to read and review it.