Summary: Naruto Uzumaki, the 7th Hokage of Konoha, Jinchūriki of Kurama, hero of the elemental nations, and good friend from many, died from a mysterious illness. Never in his imagination would he have thought to open his eyes inside the body of someone who looked exactly like himself when he was around 18 years old. "Now that's unexpected."

"Speech."

'Think.'

Magic/Technique/Jutsu

Flashback/Events of the Past

Warning: English isn't my native language.

Disclaimer: I don't own any material used in this crossover fanfiction.

He needed to block a few punches from Haku, and when both were close to the ground, both pushed themselves off each other to gain some distance. They both landed on the ground, looking at each other. Both began to circle each other, trying to find an opportunity in the opponent's stance or defense.

'Haku… I am sorry that you got drawn into this because of me. I promise you, I will do anything in my power to end this as fast possible,' thought Naruto. He flexed his legs, vanishing out of nowhere. Haku narrowed his eyes, looking behind her before turning around in a flash. She blocked a strong kick from Naruto, who just appeared before retaliating with a punch to his face.

Naruto leaned his head to the side, dodging the swift strike in the last second. Haku grabbed Naruto's head with his hand that just missed his head, letting Naruto's eyes widen for a second before he grabbed the arm that tried to stab him with a senbon. Both tried to overthrow the other. Naruto struggled with the intense pain he was still feeling because of the war that was raging inside his body.

It was only thanks to his inhuman pain tolerance, willpower, and experience that he didn't become unconscious from the extreme pain. Others wouldn't even be able to move like Naruto under the extreme pressure their body would be under.

'Come on… remember!' thought Naruto. He felt how Haku slowly was about to overpower him. He was lifted off the ground and was thrown away. Naruto got hit by many senbon on his body, letting him wince. He somehow landed in a crouch but had a hard time moving his body with all the senbon out of black energy sticking in his body, pressing on special points to make it harder for Naruto to move.

'If only I could use my chakra somehow… I can't use it while it fights this unknown power inside my body… tsk,' thought Naruto. He didn't want to do this, but he had no choice. He took another deep breath, feeling how his blood vessels nearly burst.

"NRGH!" he coughed up blood when all the senbon flew off Naruto's body as if something pressed them out of Naruto's body. He gasped a little but had little time to recover because he saw how Haku appeared over him in a flickering motion with ice-formed claws around his hands.

He had to roll to the side and nearly failed because of the extreme pressure he placed his body under. The breathing technique he just used the second time to flood his body with immense amounts of oxygen was a Taijutsu technique he developed with Rock Lee back in the day. It was an alternative to the Hachimon Tonko (Eight Inner Gates).

They both called this technique Shichi Tenkohō (Seven Heavenly Breaths). Every time the user used this Taijutsu, they would gain enhanced physical abilities. Every time this method was used, it put the body under more pressure, making it possible to use this ability as much as the user wanted until the body could no longer handle the amount of oxygen in the body.

Naruto's current body couldn't handle more than two times using this technique as it seems. He already guessed that since he felt extreme pressure after using it the first time to fight Haku somehow.

If his body wasn't under so much pressure from the unknown force that fought his chakra inside his body, he could use this technique more often, but this wasn't so important right now. He had to remember the feeling he once had during his battles against enemies far stronger than Haku.

Naruto jumped up from his low position. 'I don't know if Guy felt this much pain during the times he fought Madara with his eight gates, but this is pretty intense,' thought Naruto. He made himself ready for Haku's next assault when he saw how Haku suddenly relaxed his body.

He narrowed his eyes when, beside Haku, another shadow began to rise. The shadow took the form of a human before gaining details, as Haku did.

"Oh, you got to be kidding me," said Naruto. "Of course, it has to be Zabuza. Who else." He already had a hard time fighting Haku alone, but now he had to face off against both of them. This won't end well if he keeps up the current pace.

He closed his eyes, thinking back to all the training he had done over the years in his past life. He already felt how his body naturally reacted to his thoughts since he came to this Trial. He needed to remember more. All the times, he fought and was in close proximity to dying.

All the time, he used his chakra to enhance his body in ways that were never done before—all the things he experienced. Zabuza and Haku were readying themselves, but they waited for something. It was like something was telling them to wait for a second before charging Naruto.

Naruto opened his eyes when he felt a strange sensation of peace and quiet around him. The intense pain he felt so far had vanished. His mind was calm, his thoughts were flowing like a river, and he didn't hear anything from around him.

Even when his body still battled the unknown force, he had found it again. The state he was in when he was on death's door. Haku and Zabuza flexed their muscles before both vanished in flickering motion. Haku appeared before Naruto while Zabuza appeared behind him.

Haku had created a thin sword out of ice while Zabuza wielded his Kubikiribōchō. Naruto first looked at the sword made out of ice, which swung in a horizontal arc to decapitate him. Naruto calmly looked over his shoulder, seeing how Zabuza swung his huge sword in a vertical arc from above to split Naruto into two parts.

Just before one of the two swords could hit Naruto, he had channeled the chakra to his legs. Even when the unknown force still tried to suppress Naruto's chakra, it failed after Naruto entered this state of calmness and concentration. Naruto vanished out of nowhere and appeared a little away, forming a fist with his right hand. Some could clearly see the chakra that was being focused in his right hand before he punched the air.

'Fūken!' (Wind Fist) A strong stream of air shot out of the fist. Haku and Zabuza jumped in the air, forming hand signs already. Naruto vanished again just to appear over Haku with a raised leg. Haku tried to turn around in time, but Naruto already brought his leg down in a kick and hit Haku on the back.

'How could I have forgotten?' Naruto looked to the side and saw how Zabuza swung his huge sword to kill Naruto. Naruto flexed his leg muscles, suddenly jumping higher into the air as if he had jumped off the air itself. The sword missed Naruto before Zabuza threw his huge sword toward Naruto.

Naruto twisted his body in mid-air, feeling how the sword made a small cut on his right leg. He didn't flinch and simply looked at Zabuza when he turned his body back toward the former demon of the mist.

Zabuza pulled his arm back, revealing the thin wires he had attached to the blade. Naruto saw the flash of a very thin black wire attached to the huge blade out of black energy. Naruto only had a second to react, but he could dodge the blade that returned to its owner because of the wires that were attached to the blade.

Zabuza landed safely on the ground, catching his sword in one hand, observing Naruto at how he landed 20 meters away from him.

'Everything goes back to the basics,' thought Naruto. Zabuza and Naruto began to run toward the right, looking at each other. 'It doesn't matter how advanced a technique is. Everything is based on the very foundation of chakra manipulation. There aren't basic or advanced techniques. There are only techniques.'

Unknown to him, his ocean-blue eyes began to shine with a blue light, similar to the eyes of Zabuza right now. Naruto didn't even realize it… But he wasn't using chakra at all at the time. He had been using a different source of energy since he came into his first trial.

It was the unknown force he felt inside his body that was fighting the chakra and the power he felt inside the Colosseum. It felt pretty similar to Naruto, and that was why he didn't even realize it in his current state of nothingness, concentration, and focus.

A power source so ancient that no one even knew it existed once. A power source so pure that it had no corruption, twists, or any other negative forms. It was the very essence of life itself that transformed over millions of years into dozens of new energy sources.

This was the reason why, even when he was currently forming a spinning sphere of this ancient energy source over his right palm, he didn't go against the rules forced upon him because of the quest he accepted, which was only to use basic chakra techniques.

Normally, Naruto would have died on the spot, but since he used another energy source besides chakra right now, he wasn't breaking any rules. Zabuza's eyes narrowed at Naruto's newly formed Rasengan in his right hand. The spinning sphere of blue energy was radiating the very essence of the energy Zabuza was made of right now.

Zabuza knew it instinctively… if that technique would hit him, he would die. But he got the command to attack Naruto into his head, just like before. So… he did the thing he was told to do. He readied his sword and charged at Naruto. Naruto stood still, only observing Zabuza.

Naruto didn't react when multiple clones of Haku appeared around Naruto, charging him. Naruto saw the real Haku appearing behind Zabuza, forming hand signs. Naruto only walked forth, and when the first clone of Haku was beside him, he dodged the blade out of ice.

The clones tried to hit Naruto with their limps or formed weapons out of ice, but they couldn't hit Naruto. He weaved through all the attacks like he was dancing, with his Rasengan in his right hand, ready to attack if he wanted.

He stepped to the left to dodge a sharp ice projectile, lowering his head a little to escape a deadly ax-swung, just to twist his body to the side to dodge the kick from another clone. He slowly but surely made his way through all the attacks of the clones, coming closer to Zabuza with every step forward.

Zabuza didn't stand still either. He was still rushing toward Naruto but stopped when Naruto suddenly vanished between all the clones. He gasped when something was slammed into his back, causing him to feel extreme pain. He felt how his body began to be torn to shreds.

Naruto had appeared behind Zabuza with his Rasengan made out of the ancient energy source before he slammed his technique into Zabuza's back. Zabuza began to spiral away from the extreme force, and when he slammed into the ground, his body exploded into multiple rays of shadowy energy before the energy vanished.

Naruto looked back at Haku, who had just made his last hand sign. Naruto could feel the temperature drop around him and Haku. Multiple mirrors out of ice formed like a dome around Naruto. He could observe how Haku walked into one of the mirrors before he appeared in every single mirror.

Naruto's body was surrounded by shadow-like energy when his eyes shone blue, a little stronger. The chakra inside his body tried to reach out to Naruto, but the unknown force that suppressed his chakra hindered it, letting Naruto not realize what truly happened inside his body right now.

The ancient energy source was slowly but surely gaining the upper hand over the chakra, making it possible for Naruto to use it as he did in the fight.

What would be the end of this power struggle inside of Naruto's body? Would Naruto reclaim his senses and return to his roots, or would he embrace the new power he got and use it from now on? Only the conclusion of this trial would hold the answer.