A/N: Back for another chapter… Sakura's intelligence is something I am trying to make a lot more use of in this AU story.
"Alright, Sakura, remember infusing a change in chakra nature is about creating the proper physics for each nature." Kakashi began calmly.
They were at the training grounds within the village, it was mid morning.
"Most of the time, we infuse these changes to Jutsu's, but you're trying to infuse it into raw chakra and apply it to your hands." He paused. "Now, what is your primary chakra nature?"
"Earth, but I would like to eventually infuse an individual nature into both of my hands and feet." She said eagerly.
"Start with one at a time and work your way up to four, you'll have to forgo one of the five." Kakashi advised her.
"Lightning release, I've never had the stamina or speed necessary for lighting-based ninjutsu anyway," Sakura admitted shyly.
"That's nothing to be ashamed of, Sakura. As a lightning nature myself; it is the most physically and mentally demanding among them. Now, let's start with the easy part, focus your unchanged chakra into your hands." Sakura nodded, doing just that.
"Great, Sakura. Now, the hard part is put as much energy, mental and physical, as you can into forcing the chakra around your hands into stone." He instructed slowly.
Sakura tried for several minutes, even shouting as she clenched her fists, but the chakra enveloping them did not change from its raw state.
"It's not working." She said anxiously.
Kakashi was nonchalant. "I didn't expect you to get it right away." He continued calmly. "If it helps, imagine the destructive physical power of the earth itself and all that comes with it."
"…If that's-then…form from nothingness, spiritual energy… Okay, yin release is key here." She thought quickly. "This time, I've got it!" She said with focused confidence.
There was nothing initially, but with a bit of time, Sakura's hands, enveloped with chakra, were encased in hardened earth, skin and all.
"Excellent, Sakura. You have extraordinarily efficient chakra control, something not even all the Kage can say." Kakashi said, impressed.
"My hands are heavier," Sakura said, studying herself.
"You don't seem to have trouble adjusting to the weight." He observed.
"After dealing with the pain from the Hashirama cell mutation, heavy hands are nothing," Sakura admitted bluntly.
"Let's see how confident you are after some hand-to-hand," he said, also blunt.
"Not without practice infusing more than one chakra into my Taijutsu first," Sakura said, looking determined.
Kakashi was rhetorical, but I admired her for having such a challenging goal. "Other chakra natures won't be as easy to maintain; that's why we all have our primary nature. Fighting with four out of the five chakra natures infused into your Taijutsu at one time is ambitious, Sakura. You know this training goes as far as you. Your determination drives you." He reminded her seriously.
Sakura worked on water infusion next, deciding this chakra nature was best for her feet, dispelling the earth infusion, choosing to master one at a time for simplicity's sake—maintaining four chakra nature infusions would come at the end of this training. As it turned out, walking with your feet enveloped in water-infused chakra was not quite the same as waking on water itself, every step had more weight.
"Damnit." She dropped to a knee, exhausted, and her water chakra infusion vanished.
"Maintaining an infusion of your core chakra nature is easy; other natures will be more difficult; what you're trying to achieve is brand new," Kakashi said bluntly.
I've been working on fire release, but earth and water are my best." She sighed.
He was rhetorical. "My suggestion is to forgo water chakra infusion for wood infusion. The wood release is part of your body on a cellular level now…"
Sakura nodded thoughtfully. "Wood, earth, fire, and wind, I've never actually tried to use wind release before, let alone create a wind chakra infusion."
"There is a first time for everything, but maybe save more for another day," Kakashi said.
"No, " Sakura stood up again defiantly. "I'm not stopping." There was silence while Sakura attempted fire chakra infusion into both hands. "I don't care if I can only keep a fire infusion going for a minute; no holding back, Kakashi-sensei." She demanded seriously.
Using lighting ninjutsu as his specialty, Kakashi was used to the effect large amounts of heat had on his body. Still, he steeled himself for the likelihood of being burned by fire-infused chakra emanating from Sakura's readied fists.
"To think she used to scream with fear during her earliest days of ninja training…." Kakashithought quickly to himself. "It looks like my days of reading while you try to hit me are over—Here I come." He said calmly.
Sakura and Kakashi immediately rushed at each other, becoming locked in close combat. Her first few punches collided fist-to-fist with his…
"It's like her fists are made of flame; I need to push her farther…." Kakashi had to admit that every punch from Sakura had him feeling the heat as their prolonged hand-to-hand continued faster.
"I'm going to burn the mask right off his face!" Inner Sakura said.
15 seconds…
Kakashi had to focus on defense and look for an opening to attack; it was soon clear Sakura was trying to break his concentration by attacking his face.
Sakura knew that the speed of Kakashi's hand signs was always lightning fast, and his reaction time was much the same. Still, her flame-infused chakra punches were she noticed, slowing his evasiveness…
Yet, Sakura wasn't sure how much longer she could maintain this fire infusion of her chakra. Still, she stayed focused; his latest block was imperfect, his timing slipping, which gave her a small opening to knock him off balance…
30 seconds
The small burns Kakashi had sustained as they sparred meant that he couldn't match Sakura's punches the same way every strike, and as they began to mount, Kakashi was forced to admit that Sakura was smart for her idea. He was backpedaling entirely now.
45 seconds
As they continued this exchange of fists, Sakura began to feel the strain of maintaining the fire-infused chakra, so she made sure to put as much speed behind her punches as possible.
75 seconds…
Kakashi was surprised but impressed that Sakura was getting faster, but he could see the strain she was under, so he decided to wait and see how long she could sustain things. It happened suddenly; Sakura's fists came at his chest, pushing through his latest block and leaving quite a sizable burn behind. The fire infusion was gone moments later as Sakura doubled over.
"I'm done for now…you were right; other infusions will be harder to maintain." She admitted, her hands shaking from fatigue.
"That had to be more than a minute; most of us wouldn't even be able to attempt what you're doing, let alone sustain it." He told her praisingly.
"I'll heal you; then I'm going to spend time with Naruto." She tended to Kakashi's burns.
"You'd be better off to spar against Naruto. I'm not particularly interested in exerting this much energy multiple times daily." He admitted casually. "Naruto will have the energy to spare, and since this was your idea, what will serve you best is someone willing to spar much more frequently than I am." He chuckled. "Besides, Naruto is far more skilled with wind release so that he can help you with wind infusion. I don't think you need me for anything more when it comes to mastering this infusion technique."
"Aw, are you getting old, Kakashi-sensei!" She teased.
He laughed. "I wouldn't go that far; I can fight for days if necessary, but the war is coming, and apparently, what I think matters to the Allied Shinobi Forces, which means that I spend most of my days talking battle strategy.
Sakura smiled. "Good preparation for being the Sixth Hokage."
He scratched the back of his head embarrassed. "I don't know how many people think I'm qualified to be the next Hokage."
"You have the respect of the village and the experience as a ninja to lead the rest of us." She said rhetorically.
"That doesn't mean I'll want to do the paperwork." He said with a sigh.
Sakura laughed. "Yeah, I don't think Naruto realizes that comes with the job…" She sighed. "Speaking of, I should go find the world's most unpredictable ninja; I'll see you, Kakashi-sensei."
Kakashi watched Sakura run and leap out of sight with the feeling that she wasn't too far off from surpassing Tsunade, just as Naruto had already surpassed Jiraya… As for Sasuke, he had no idea what became of him after their most recent confrontation but Kakashi knew all three of his former students were among the most talented and influential in the ninja world…
Sakura couldn't find Naruto at the ramen shop or in his apartment but she knew he was in the village—with the war so close missions had scaled back…
She sighed. "I bet he's training somewhere."
Tsunade was walking towards Sakura, shouting bluntly from some distance away. "Sakura, why didn't you let me know that you asked Gara for a favor!"
"Didn't Naruto tell you? He needs a new chakra crystal since he broke it in his six tails state during his fight against pain." Sakura said seriously.
"My grandfather's chakra crystal—the necklace I inherited years ago…broken?" She said, taken aback.
She sighed. "You were still in your coma, if not for Minato planning for after his death Naruto's seal would have broken. I knew Gara met the Hidden Stone Kage so I asked him to talk to him about making a new chakra crystal." She said bluntly.
"Well," She pulled out a scroll and tossed it to Sakura. "Then this belongs to you; the stubborn old man isn't normally so cooperative."
"He gave Gara the information?" Sakura asked, surprised.
Tsunade nodded seriously. "It's not overly difficult as it turns out, but it is draining—I read all the mail that comes into the Hokage office." She added at Sakura's questioning look.
"Thanks for bringing this to me, Lady Tsunade," Sakura said with a nod.
"If you see Naruto, tell him that I want his time as payment for breaking my necklace!" She said bluntly.
Sakura was admittedly grateful Tsunade wasn't overly upset but she had learned quite a while ago that she thought her necklace cursed, which wasn't surprising with all her suffering, not that Sakura knew the details.
"I will, see you Lady Tsunade." She said, putting the scroll in her pocket.
Sakura decided Naruto was probably training in front of the same waterfall where he had previously worked on mastering his natural affinity of wind, which she knew had led to the creation of his Rasenshuriken… Her hunch was correct and when he came into view, he was meditating in sage mode. It made her realize how mature he was now, granted the louder parts of his personality were still very prominent. It was rare for Naruto to sit still and even rarer that he was completely silent. Sakura stood contentedly watching him briefly before meditating with him…
Naruto was the first to break the silence several minutes later. "All done training then?" He said with a smile.
"Well, I wanted to take a break and come find you." She pulled out the scroll. "Gara talked with the Kage of the Hidden Stone about Chakra crystals; it feels like one is in the scroll. You could start training to control the nine tails chakra."
"What about your training Sakura?" He asked.
She insisted. "Don't worry about me, Naruto. I mean, I appreciate it, but Chakra nature infusion is about endurance, I can do that anytime."
If there was anything Sakura fully understood about Naruto it was his modesty. She knew that he wouldn't and didn't see himself as a bigger part of the war than his comrades, whether he knew them well or not.
"But I'm dangerous in my tailed-beast state." He reminded her.
"I know what I signed up for when I decided to get injected with Hashirama Cells, and I promised to help you work to control the nine tails power, let's go find Captain Yamato."
"Sakura… Thank you." He said emotionally.
"No need to thank me, I love you." She said softly.
"I love you too." He said taking her free hand.
Yamato was surprised to learn that the Hidden Stone responded so fast…
"I can't believe it, it's a chakra crystal." He said slowly.
"Then we can start to help Naruto master the nine tails chakra!" Sakura said calmly. She took several minutes to read the information included within the large scroll. "Okay… I think I get it; we can open the smaller scroll now and I'll imbue the chakra crystal with the proper sealing jutsu, but first, Naruto the crystal will have to come into contact with you, it will remember the nine tails chakra." She said seriously.
"What? You mean I need to purposely… He stopped, trying to comprehend this implication.
Sakura continued to explain. "Well that will be a part of the sealing jutsu—the thing that triggers the crystal, which will be a stronger version of the Jutsu Captain Yamato has used on you."
"So I have to?" He said hesitantly.
"Don't worry Naruto." She assured him gently.
"If you get badly hurt like pervy sage— "
"Trust me Naruto." Sakura said reassuringly.
"I know, I do trust you." He said calmly.
"Good, because everything I have done recently is because I love you so much!" She reminded him affectionately.
"That's something that I won't ever forget." He said.
"Then let's get started." She said, smiling calmly at Naruto.
...
"So will it work?" He asked.
"I've done everything that the instructions said, so it should," Sakura told him.
Naruto put the chakra crystal around his neck; it was pink this time. "So it's a different color."
Sakura nodded. "Needed a little of my DNA so that the crystal would respond when I'm trying to suppress the nine tails. My hair was the easiest to use." Her voice became serious now. "Now for the sealing jutsu and the nine tails chakra."
"You are sure?" He asked cautiously.
"Yeah, unless that chakra is embedded into the crystal, there is no point in having it." She said.
"Okay, brace yourself; when I unlock the seal, he will take over my body." He warned.
"Captain Yamato, I…" Sakura said quietly, before trailing off.
"Don't worry, Sakura, I'll be right here if things escalate." He assured. "It's a good thing we moved to some empty land well outside the village."
"Yeah." They admitted quickly.
There was stillness and silence amongst th; Naruto closed his eyes and took a deep breath entering his subconscious where the nine-tailed fox was locked away...
Drip…drip…drip…
"Naruto, what are you doing in front of me?" The fox said ominously.
"I'm taking you off your leash, but first, I have questions about my parents I know you can answer." He said cooly.
"The brat without a clan told you, she is just like your mother Kushina was, thinking that she could control me, that didn't end well for her!" He was quite mocking.
"Why did you kill her!" Naruto's anger was rising now.
He laughed. "She was already doomed when I was forcibly extracted just after she gave birth to you." He said cheerfully. "Your father decided to play hero and stop Madara; I regained my senses long enough to destroy the village that insisted on keeping me tied to your pathetic clan. Uzumaki is like cockroaches. You live much longer than you should. Even after your mother suffered my extraction, after my claw impaled her gut, she still suppressed me long enough for Minato to take half of my chakra with him using the reaper death seal and sealed what remained inside of you." He was bitter now.
"I wish I could kill you!" He said with burning rage, but I'll settle for taming you."
"You don't have the power to suppress my chakra, that rage is perfect for me!" He said sharply.
"Well then I guess I'm going to find out if I'm really my mother's son!" He said.
"You would unlock the seal knowing I could take over your body?" He laughed harshly. "Fine, let's see what you're made of, Naruto Uzuimaki."
After a long silence Naruto approached the lock and, with his right hand, readied the key to his sealing formula (chakra appearing on the tips of his fingers and thumb) before unlocking the seal…
Sakura and Yamato were waiting quietly when the familiar red chakra cloak suddenly began to bubble around Naruto…
"There it is, the nine tails cloak!" Yamato said hastily.
Sakura shook her head. "We need to wait until the fourth tail appears. Then the crystal will be bathed in the nine tails chakra and I can perform the sealing justu."
Yamato was hesitant. "Sakura, are you sure?"
"Yes!" She said bluntly.
Meanwhile Naruto jumped out of the way as soon as the fox was freed from his cage. He could already feel its chakra trying to catch him…
"Let's see how long you can run, Naruto!" He said darkly.
"I'm not running." He said, trying to keep the nerves out of his voice.
"Your power is no match for mine, I will overwhelm you like I always do!" He said triumphantly.
"Come get me!" Naruto said anxiously.
The chakra of the fox was immediately intense, the hatred was overwhelming and the rage unparalleled. Naruto was engulfed by it…
"Yes, he has finally given up; I can feel it." He laughed out of enjoyment.
"What are you laughing at you stupid fox, did you forget that I'm in here too!" Sakura said defiantly.
"That voice it's the Haruno brat, you can't save him now!" He said bluntly.
"You sure about that!" She was goading the fox now.
"If you want to die, I can make that happen!" The fox said threateningly.
Captain Yamato and Sakura were watching Naruto carefully; the fourth tail had appeared, accompanied by the same explosion of dark chakra seen twice before.
"The fourth tail, Sakura, I hope you know what you're doing!" Yamato said anxiously.
"I didn't spend weeks studying the Fourth Hokage's notes to fail." She said rhetorically. "Stay back; he is going to come after me!"
Sure enough, now in his tailed beast state and without any reason left, Naruto attacked Sakura, forcing her to jump out of the way repeatedly.
"Okay, but I'm stepping in if the sixth tail appears," Yamato told her, she nodded.
Sakura knew that she had to get in close to perform the sealing Jutsu properly, but the continued barrage of attacks she needed to evade made this problematic.
"Come on, Naruto, fight back!" Sakura shouted with conviction. "I don't want to hurt you but I will if the nine tails forces me to." She sighed. "I'm not sure how long I can keep my chakra in your subconscious before I start depleting my reserves." She muttered quietly.
Suddenly Naruto unleashed a roaring chakra wave which instantly leveled much of the surrounding forest space.
The nine tails was true to its intent on killing Sakura…
The raging fox roared. "You can't keep this up forever, you talentless brat!"
She was defiant."I'm just waiting you out nine tails; Naruto is still in there somewhere; he let you take his body on purpose."
"I don't know what you're planning, but Naruto has never been able to handle my chakra!" He said harshly.
"You're right, but I'm different than the last time we met, I know you will figure it out soon!" She said bluntly.
The fox was impatient now. "There is something different about, your chakra much stronger than before, it rivals Madara Uchiha now but it's not ominous… Wait, it's… No, it can't be Hashirama was the only one with chakra like that, he could control my power at will, but I know that you are not his descendant. What are you?"
"I have his cells." Sakura said bluntly.
"Wait, I remember, that's just like the one who suppressed my chakra the first time I took over Naruto's body, along with that wretched chakra crystal the one I destroyed." He was infuriated once more.
"I figured you would realize eventually." Sakura said bluntly.
"No, I won't let anyone suppress my power again!" He said angrily.
"We'll see about that!" She warned. "Naruto, come on already, this is your subconscious, fight back!" Sakura thought emotionally.
The surrounding forest was now in ruins, and both Sakura and Yamato were still dodging the increasingly devastating attacks of Naruto's tailed-beast state… Abruptly there was a wail that was half man and part beast…
Yamato was astonished. "Incredible, Naruto's trying to stop the nine tails through sheer willpower!"
"SAKURA— " An even longer wail between beast and man then, "…ARRRGH, NOW… DO IT!" He shouted, but it hardly sounded like his own voice as he struggled against the nine tails will...
Sakura weaved the necessary hand signs as she carefully closed the distance between herself and Naruto… "Hokage Style Elder Jutsu: Tenth Edict on Enlightenment!"
Just as Naruto was feeling like his willpower had lost out to the nine tails, Sakura's right hand connected forcibly with the newly readied crystal around his neck an, and he found himself somewhere amongst all the rage of the nine tails…
"Naruto, don't worry!" She somehow remembered exactly what Yamato had done that day at Tenchi Bridge; conjuring forth an area of ten surrounding pillars while the necklace responded to her chakra, which she used to suppress the nine tails. It pained her to hear Naruto in agony as the chakra steadily receded and his wounded body returned to normal, he collapsed from exhaustion…
The nine tails was enraged now. "I've been tricked!"
"I think it's time you get back in your cage!" Sakura said impatiently.
Something invisible forced the demon fox back into his cage and it shut.
For the first time he looked truly confused. "What is this?"
"The Yang seal I created doesn't just allow me to keep Naruto's mind free of your influence, it also gave me access to the sealing formula's key." Sakura said bluntly, before locking the seal once again.
The fox looked murderous at the realization. "Naruto did this on purpose, to share control over maintaining this damn seal with you!" He said slowly.
"Well, yeah, but the chakra crystal was the bigger priority." She sounded very matter-of-fact, "I'm nowhere near the skill level of the First Hokage, so I needed to imbue the crystal with your chakra, or it wouldn't work like it's supposed to in the future."
"I'll eventually break the crystal, I've done it before; it's only a matter of time..."
"Yeah Naruto will have control someday." She warned.
Sakura had to admit that she had no idea when that would happen. Sakura made sure to banish the ring of large wooden pillars before running to an unconscious Naruto's side. It took several minutes of healing him to care for his wounded body and even longer for Naruto to regain consciousness...
Naruto stirred slowly. "Uhhh…" He tried an failed to sit up feeling totally exhausted. "Sakura?"
"Lie still," She said gently.
"I remember bits and pieces…" He said quietly. "Did it work?" He asked quickly.
"Yeah, everything is fine now." She said, squeezing his hand.
"So then I can start trying to get control of the nine tails?" He asked.
She chuckled emotionally. "I think we've both been through enough today; let's worry about more training tomorrow; I'll take you for some ramen."
"I don't think I can move, let alone lift my arms to eat." He said seriously.
Sakura found that she was smiling. "Well then I guess I'll have to help you for a while."
The truth was that whether Naruto needed help or not, she didn't mind at all...
A/N: I don't have a template for how chakra crystals are made, so I thought I would make it easy on myself. It makes sense to me, so… Anyway, Naruto's tailed beast state leaves his body pretty battered and bloody. Sakura will need to put in overtime healing him as I'm not going to make gaining control over Kurama as easy as it was in canon.