Dix's chakra reserves were almost endless, so it was incredibly hard to quickly fill up his body with natural energy. During the 10 days he used a huge amount of clones to exponentially increase his experience gathering, just like before. He was sucking natural energy inside his body faster and faster, his control was getting better and better, and due to his sensor ability his inner-sense was extremely fine, almost reaching the molecular level. This way he could optimize the balance of the three different energies at utmost efficiency.
He finished the training at the fraction of the time the original Naruto needed. He was able to use so many more clones to train natural energy control, simply because his chakra reserves were astronomical in size. This made everything faster, not to mention that two separate teams were working on perfecting Sage Mode. At around the 10th day he didn't need the oil anymore and the clones mostly finished with the non-moving part too.
When it came to combining the two practices he finished during the 10th day, and by evening he was considered a Sage himself. His appearance changed the same way as it did in the anime: an orange circle appeared around his eyes and his pupil turned into a horizontal toad-slat. By that time if Fukusaku were to look at him with natural energy detection he could see the kid as a huge vortex that sucks all energy away from its surroundings. It was a bit terrifying to see.
All the while the 1000 clones he left behind at HQ didn't dilly-dally either. They decrypted and analyzed every single scroll and book they found, and soon research started in earnest. By the time Dix finished with the Sage training most of the storage-seal related knowledge was deconstructed and some usable seals were made. There was one in particular he needed, that's why it was finished first with extra focus on it.
For senjutsu to work you need natural energy, but to gather natural energy you have to stay absolutely still and become one with Nature. The original Naruto handled this by summoning clones to gather for him while he fights. Dix will obviously handle this with seals. The R&D at home was able to make a passively working seal that can automatically gather natural energy and adjust its level to be balanced at all times.
It achieves this by a few different cores. There are 4 that are only there to gather the energy, while a bigger one that is connected to all of them is meant collect and redistribute. It has master control over the other cores to turn them off when the balance is already met and Dix is not actively using it, or on when its a combat situation and natural energy is being used. This is the marvel of modern technology!
Next R&D will try to do something with the dimensional seals, but that's a way harder nut to crack, so it will take a while.
When Dix finished with the training he was offered to be taught Frog Kumite, the uniform fighting style of Toad Sages. He promptly refused and said he can take care of the rest. He achieved everything he needed, so he didn't have to hide his abilities anymore. He took Jiraiya with him back to Konoha using FTGT, which earned him some abashed looks and gasps. He didn't care too much, so he moved back to HQ right away to master movement and combat in Sage Mode. He used a lot of clones and some time, and it was done already. He also had to return for the new seal to be implanted, because it was only possible there.
He also had to get one specific thing done. He avoided that for months now, but because he found the ruins it was impossible to drag it out anymore. He found a few books and scrolls there about the seal that was holding Kurama in place. That was only logical, and Kurama would think the same. He couldn't possibly explain why he doesn't free him after finding such a treasure trove of knowledge.
Dix found himself a spacious secluded room, then sat down in the middle and started meditating. He reached all the way down trough his subconscious to reach Kurama's cage.
"Haven't seen you around here in a while. Is it time?" came the low rumbling, but excited voice as soon as Dix opened his eyes in Kurama's chamber where he was locked away.
"Yes, you have seen the ruin I took over, it had the necessary knowledge to let you free. I have the key to unlock you, but I have to ask. Are you really willing to help me?" Dix asked with a very serious face and tone. Kurama's fox face was distorted by the surprise and he was left with a stupefied expression.
"What do you mean? I have already pledged my allegiance to you, what else do you want? Am I really so untrustworthy?" asked with anger hiding in his voice. It was a bit of a stretch from Dix's part, but he was worried. The original Naruto used almost two decades to slowly soften up Kurama and gain his friendship. Dix skipped all that and tried to win Kurama over with a lie. He didn't know if it was actually believed, or that Kurama was willing to fight to save the world.
"I'm sorry Kurama, but I have to know. I know your story. And I know it was hard on you for many years before. Right now we are fighting to save the world. Are you really willing to work towards that? I have to know what you really think of this, because I won't have many corners to cut if you decide to bail on me at the last second."
"What are you saying? I already gave you my word, and that won't change. You brought with yourself the old man's plan, and I won't turn a blind eye to that. I only respect strength and the old man. You represent both, so you don't have to worry about me. I'll stand besides you."
"Thank you Kurama. I just wanted to make sure. I'll release you now." With that Dix reached with his right hand towards his stomach. On his fingers small purple flames started burning, as he closed his eyes and focused on the seal. He then twisted his hand in an opening motion, and suddenly the huge metal bars in front of him started crumbling.
Kurama patiently waited for the doors to completely open, then he started rapidly distributing his chakra throughout Dix's whole consciousness and body. For a second he tensed up at the prospect and though he was lied to and is being taken over, but after some expansion, Kurama turned back and went back to where he was accommodated before.
"Sorry, but its been quite a while since I could stretch myself out a bit. Your inner plain is quite spacious by the way. You really became strong. Here, I'll give you my chakra, I know you want to start training with it right away. I'll stay here. We will have a direct connection, so you can speak with me anytime you want."
"Great, thank you Kurama. I'll count on you, partner!" Dix finished the conversation, gave him a thumbs up, then disappeared with a big smile on his face. When he came to he was already coated in the Nine-Tails chakra.
The Nine-Tails Chakra Mode and its related forms coat the user's body in yellow chakra, which emanates from them reminiscent of flickering flames. The form's design differs between users and can even change over time, but certain features are consistent across all forms: two horns on their head, six magatama markings around their neck, some sort of prominent circular or swirl design over their stomach, and various other lines extending along their body. This was the first design Naruto managed to unlock in the anime, but it quickly transformed into the real Kurama mode, that was the sign of their cooperation.
Dix's pupils became slitted, the whisker-like markings on his face become thicker, and the chakra shroud's shape altered to resemble a full-length haori, similar to the one Minato usually wears. For all intents and purposes, Kurama Mode is a completed version of Nine-Tails Chakra Mode, meaning Dix will be able to manifest Kurama's shape trough the chakra coating his body.
Next he tried combining his Kurama form with Sage Mode. His pupils become a combination of the two forms: the vertical fox-slits with the horizontal toad-slats. Even more interesting was when he tried activating his EMS his eyes turned into an intensively glowing combination of blue and yellow, it turned into a beautiful jade-green color. Also most of the EMS's design stayed the same, except the middle of it where the Kurama + Sage mode cross appeared.
The previously half-lit room was perfectly illuminated by Dix's glowing coat. He knew shit is going down, so he summoned a clone with the same settings to see how he looks like. It was the coolest thing he has ever seen. He and the clone was circling each other to take in all coolness that they worked so hard for. Also the powers. Unimaginable, unlimited power!
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