Disclaimer: First Chapter
Story Start!

No amount of planning helped Sona Sitri win.

It wasn't a complete slaughter, because Rias could not predict just how good that Sona would off her peerage, nor the strategies that were made to combat certain members of her peerage. Issei had actually gotten taken out in his Balance Breaker by attacking one of her peerage's mirrors and inflicting massive damage onto himself. Asia had also been taken out, though that wasn't impressive.

Otherwise, it was a one sided win.

Now, back at school for the moment before her next Rating Game, Rias and her brother were both standing nearby each other.

"Sirzechs?"

"I heard you achieved a Transformation... and this guy was going to help you control it. I figured, maybe it was time I took on a teacher." Sirzechs had his own transformation that he had very little control over. He wanted to see how Rias was going to train to control her transformation, and maybe take some notes or hire Naruto for his own training.

They were waiting for Naruto though.

He was late.

"Sorry I'm late, I was getting Rias' training tools." Naruto had large golden hands coming out of his body and carrying boulders of various shapes and sizes above his head. He had a good reason for being late at the very least, since it was hard to find boulders that he could cut into the correct shape. He had over 16 boulders cut into so many different shapes. Most of them were different types of rectangles or triangles, but there were some spheres in the mix as well. "... did you sign up for this training too?" Naruto asked when he saw Sirzechs.

"I mean... can I?"

"Got money?"

"Yes."

"Then sure." Naruto put all of the boulders on the ground, before he pulled all of the chakra arms back into his body except for one of them. "Use your Power of Destruction to stack these blocks." Naruto told Rias flat out.

"Eh?"

"Eh?" Sirzechs asked as well as he looked at the impossible shapes of the "blocks" that Naruto was talking about. The rectangles would be fine, but the spheres and prisms would be impossible for anyone to stack. Not to mention using the Power of Destruction to do something like that would make the challenge even harder, when it was already impossible.

"How?"

"I've seen you change the shape of your attacks, just control it, tune it, and make it the shape of a hand. The stack it." Naruto stated as he started to stack the blocks with a controlled chakra hand, stacking them all perfectly onto each other. Not a single block had a crack on it, and the tower of blocks didn't so much as wobble as he stacked.

Sirzechs ate his words that he was glad he didn't speak.

'That is such fine tuned control. He's using such a large amount of energy, but the boulders aren't being so much as cracked... and he's still managing that level of control while focusing on stacking the blocks in an impossible way.' Sirzechs looked at it with not hidden interest.

Naruto slapped Rias on the ass.

"Transform already Rias."

"Right Naruto-sensei!" Rias realized that the lesson had already begun, and Naruto knocked the blocks over so that Rias could take her turn. Her hair turned blonde again, and she covered herself with a light aura of her demonic power. She summoned her Power of Destruction, and she sent it out towards the boulder.

"Lower the output."

"Yes Naruto-sensei." Rias lowered the output.

She started to sweat a little as she started to lower the output, finding the act of controlling her power to such small degrees to be even harder than it was to raise the power. Her Power of Destruction formed a sort of hand. The shape was wavy and uncertain, but she managed to form the hand and she grabbed onto the boulder block.

It cracked.

The boulder exploded the second she lost her concentration, with pieces of the boulder being almost erased by her attack power. Her eyes just widened, and she turned her head to look at Naruto with a sorry shocked look. Sirzechs just looked on in interest.

"Get to work, you're not training by standing there. Lower your output, be gentle. If you can fine tune your control, you can reach even greater levels of power, using the power you already have. Split your focus between stacking and fine tuning." Naruto created two chakra arms, before he started to pick up blocks and juggle them. Not a single crack appeared on any of the boulders, and he tossed them towards the ground and stacked them onto each other by tossing them. "You've got some pretty rad power, but your control is going to prevent you from going any further than this."

"Yes sir!"

"I see... this type of training does make sense." Sirzechs could now understand the immense benefit behind such simple, but hard, training.

Second nature.

It would be impossible to stack the boulders until you turned your control over your power into something that came second nature to you. Once you could make it so easy to control your own power that it became second nature, only then was it possible to stack the blocks in an impossible way. Sirzechs yelped when his ass got slapped, and Naruto pointed towards a stack of boulders as well.

"You too."

"Oh... right!" Sirzechs slapped his cheeks, realizing that he was training too. He turned his body into an aura of the Power of Destruction, destroying his surroundings. Naruto waved the power away from himself in annoyance, while Rias just had a naturel defense against it with her aura. Naruto slapped the back of Sirzechs head. "Ow!"

"Do it again, but power up without affecting your surroundings. You're not ready for boulder stacking."

"EH!?"

Naruto transformed into his Six Paths Sage Mode right in front of Sirzechs, but nothing around him was destroyed or even shifted slightly in response. Naruto extended his arms and he gestured to how nothing got destroyed. Naruto transformed back to his base form.

He transformed again.

His chakra surged and started to destroy everything around them, but Naruto reigned his chakra in and stopped the destruction he was causing.

"You have such little control over your transformation. You wouldn't be able to even touch the boulders without destroying them until you manage to transform without sending out destruction. So YOU need to practice that." Naruto gave Sirzechs something that he was going to have to practice first. Naruto took a leaf that was in the air, falling out of a destroyed tree nearby, and he stuck it on Sirzechs head. "Transform without destroying that leaf."

"Uh... that's impossible."

"Do it anyway." Naruto responded.

Rias destroyed a boulder block behind them, because she had gotten distracted by her brother being given a different training than her.

-Time: 1:47 AM-

He finally did it.

He managed to transform without destroying his surrounded, and he realized just by doing that how much power he had been wasting. But forcing himself to not destroy the leaf on his head, he had been forced to conserve as much power as possible. By doing that, he realized that he had wasted over half of his power just by transforming and allowing it to run wild like he had been doing. His transformation could now be accessed without destroying his surroundings, and without wasting nearly as much power.

Rias had stacked 5 blocks.

'She's already on 5 blocks!?' Sirzechs thought with wide eyes as he saw his sister's progress, having not noticed it thanks to his own lesson. He looked at her face, and it was much more relaxed than before. She wasn't sweating anymore from the effort of lower her power to the bare minimum needed.

Her demonic power had grown as well.

It was more dense than before, her control had gotten to the point that she could make her magical energy even more dense than before.

"This training doesn't take long to complete once you get the basics down. All you really need to do is learn the minimum amount of power, and then go from there. She'll be done with this training before morning at this rate." Naruto explained to Sirzechs, since he could see the man's visible confusion. This was not the life and death training he had put Rias through before, but she was still showing results on the same speed of scale. "What?"

"... I wish you had been around when I first learned about my transformation." Sirzechs regretted that he never had a teacher like Naruto in his life. Naruto was hundreds of years younger than Sirzechs, but somehow had lived a far more fulfilled life with more wisdom. That was the problem with such a long life, your life moved so and was filled with a whole lot of nothing. More so since the last hundred years of his life had been rarely anything more than political talk and parties.

Naruto had a life time and more of real experience, and it showed when he trained students and passed those lessons on. He could only wonder how strong he would have become if he had a teacher like Naruto growing up, and had control over his transformation back then.

"Now get to block stacking." Naruto smacked Sirzechs on the ass next and pushed him towards the blocks, his own set of blocks to work with.

Sirzechs instantly formed a hand, and then instantly destroyed one of the blocks.

'Holy... fuck...' His eyes widened at the destroyed block, realizing that he had output way too much power. He looked at his sister succeeding in putting more blocks on the stack, before he slowly lowered the power and reached out to grab a block. He stopped just before grabbing the block, and he could feel himself starting to sweat under his transformation. His hands were twitching from the effort of keeping his power at the minimum needed to not destroy the blocks.

He looked at Naruto.

Naruto picked up a rock off of the ground and chucked it at Rias, and when it hit her in the butt, she yelped, but managed to not destroy the boulder that she was holding up. She looked towards Naruto with severe confusion, since he just hit her in the butt with a rock.

"What was that for!?"

"Don't worry about it, keep training." Naruto told her with a covered up chuckle.

She already finished the training for fine tuning her control over her power, now she just needed to make it second nature by finishing her stack of blocks. By morning she would no doubt have mastered her transformation to the point it was second nature to her. The demonic aura had already vanished from her body, showing that she was wasting no energy to maintain her transformation. That was a sign that she wouldn't need to expend energy to keep her power active, which would be great in battle.

"How does it feel to know that right now, your sister is stronger than you are." Naruto whispered to Sirzechs teasingly.

"She's... wow..."

'Damnit, I was hoping sibling rivalry would push him to try harder. Still, happy that he seems proud of her. Once he mastered his transformation, he'll be stronger than her again for now.' Naruto thought to himself in annoyance. Rivalry was one of the best ways to get a person to exceed their limits.

Oh well.

-Later-

"Welcome home Sirzechs... uuuuuh." Grayfia had no idea what to say.

"I'm back, and I'm tired. That training was something else."

'He... he does know... does he know he's in his True Form?' Grayfia looked at her husband take the cup off coffee from her without destroying it, and then drink it. He acted like it was completely normal for him to be in his current form, and the stranger part was that he was not giving off an aura of power or destruction. His power was completely under his control, something he had not managed in an entire lifetime of him training in his abilities.

How could one day teach a person to keep control over their power!?

-With Rias-

"Well, I'm showered up... time for school..." Rias passed by a mirror on the way from her shower, before he jaw dropped when she saw her hair was still blonde. Realizing that she had forgot to turn off his tranformation, she powered down and watched her hair go back to crimson. "Holy... I almost went to school powered up." Rias realized just how second nature control over her power had become.

She hadn't even realized that she was still transformed, spending a day in her powered form and controlling it had completely made her forget that she wasn't in her base form.

She smiled with her eyes sparkling.

She loved to see the results of training.

Chapter End!
Please Leave Me Lots of Nice Long Reviews, But No Flames Please!

NOTE!

This was training that Naruto did to maintain, fine tune, and control his initial Kyuubi Chakra mode!
I am not making a reference to Super Saiyan!
This is not "Super Saiyan" training.

I did not "give" Rias a "Super Saiyan" form, she has that form in the Light Novel.
Please stop with the constant saiyan remarks in the comments.