Mizuki blocked and parried the kid's onslaught as best he could, as he waited for the inevitable opening that would present itself. Renji's fists moved about at high speeds, coming at him left and right before changing to an entirely different angle of approach and increasing in strength with each successive hit. Mizuki found that Renji had a slight rhythm to his attacks; when the kid moved forward with an attack, he often led with one side of his body while forcing the other half back, reducing his overall profile and negating the general effectiveness of a direct counter after a block.
As soon as he found one of the boy's subtle strengths, the traitor knew he could turn it into a weakness.
Renji turned slightly as he brought his arm around for a sharp right hook to Mizuki's then exposed lower torso, but suddenly found his target leaping away and the sizzling noise of an explosive tag whizzing by his ear as he leant out of a kunai's way the instant before it reached him. Mizuki simply smirked.
The noise exploded in his ears and his hearing turned to ring static as the concussive tore up the left side of his back, sharp heat pushing into soft flesh. Renji fell to the dirt with a heavy thud and a groaning snarl. Searing pain shot up his back as he attempted to move a split-second after he was knocked to the ground.
"Time to put you in the ground, you troublesome little prick," Mizuki chuckled as he approached, a malicious grin widening with each step. Renji squirmed as he struggled to raise himself from the ground, the pain keeping him nose-first in the dirt. He could feel his organs protesting under the pain, and something told him he wouldn't last much longer without help.
Mizuki stood above him, kunai held in a reverse grip and a vicious smile curving along his face. The twisted expression expanded slightly, sickening grin widening as he raised the sharp weapon and prepared to deliver the killing blow to the boy's jugular.
The movement was quick, a slicing movement running up the side of the boy's neck; one that would have him bleed in out in mere minutes. No matter what happened to him, the genin would die without immediate medical attention and there was no way a trained medic-nin could be brought in time for him to survive. Mizuki grinned cruelly as he gazed upon his bloody handiwork, though it shifted into a heavyset frown the moment Renji burst into a light puff of smoke evaporating into the air.
'Kage Bunshin', he thought angrily.
"You're not getting away with this, Mizuki!" Iruka yelled at him the moment the other chuunin landed in the clearing with Naruto at his side, still carrying the scroll on his back. "Naruto, do it!"
"I'm on it, Iruka-sensei." Naruto made the cross-handed seal required for the technique and shaped his chakra in a shaped blast, blue energy whirling around him as he called out the name of his technique, "Tajuu Kage Bunshin no Jutsu!"
The entire clearing was covered in a cloud of sudden smoke accompanied by hundreds of individual puffing noises. The smoke cleared and Naruto was suddenly everywhere at once. Or rather hundreds of different copies of himself were everywhere around the clearing; standing along the ground in basic taijutsu crouches, sitting on the branches of trees and a few even hanging upside down by their legs out of the dark green canopy above. Naruto was everywhere, and the difference was that every single copy of him had a tangible and physical mass. They could interact with the world the same way he himself could, which means that Naruto had just literally become a one-man army.
The clones started taunting at the sight of the shocked Mizuki as he stumbled back on his hands, suddenly very, very afraid for his life. The cat-calling stopped when the call came from the army's commander called: "Sic him, boys!"
Mizuki's sightline became clouded by orange as a wall of Naruto launched itself at him, an all-encompassing wave of feet and fists. It only took seconds for Mizuki to find himself pounded roughly into the ground by dozens of impacting punches and kicks, and only a few more seconds to find himself beaten within an inch of his life. His entire body was effectively broken; the bones in his legs along with his arms were practically hammered into dust and nearly every square centimeter was covered in bruises. His ribcage was little more than tissue paper and several organs had ruptured quite neatly at the point when Naruto's clones dispersed at the beckon of their commander.
Naruto rubbed the back of his head sheepishly as he looked over to his sensei. "I might've overdone it a little, eh, sensei?"
"I guess so Naruto," Iruka answered absent-mindedly. He still couldn't quite get over how many shadow clones Naruto could produce and remain standing. The Kage Bunshin jutsu was notorious among the experienced shinobi of Konoha for the huge amount of chakra that needed to be expended in order to use the technique, to begin with. A regular genin would barely be able to handle the production of a single clone while remaining conscious, while Naruto had managed to perform a feat not even a Kage-level ninja would be able to perform without great difficulty. The technique alone made Naruto capable of fighting a war all by himself. It sure said a huge deal about the boy's chakra capacity. That explains why he can't produce a single regular Bunshin. It's not that he doesn't enough chakra; it's that he has too much chakra. It certainly explains his horrible chakra control, Iruka thought tentatively. He just hated himself that he hadn't noticed it before
He then understood the boy's true capacity, and he knew it would be a great sin not to reward it deservingly. "Hey, Naruto, close your eyes for a second."
"Huh, why should I do that, Iruka-sensei?" Naruto asked hurriedly.
Iruka sighed tiredly. Some things truly never changed, even after a life-altering experience. "Just do it, Naruto!"
"Okay, okay, no need to shout, geez," he muttered while he complied with his sensei's command. Naruto felt a cloth carrying something weighted brush against his forehead before it remained settled lightly into his tanned skin after a tying motion was felt at the back of his head.
Still playing the dumb card, Naruto asked after opening his eyes, "Hey Iruka-sensei, where'd your hitai-ate go?" All he wanted was confirmation of his actions, his existence.
"It's yours now Naruto, you've earned it." Iruka paused for a second, considering something.
"Uzumaki Naruto, you are hereby inducted into the service of the military forces of Konohagakure no Sato as a shinobi of Genin-rank. Serve your village willingly, obey your Hokage without question...and may your Will of Fire burn brightly," Iruka added kindly.
Tears shone in Naruto's eyes, deep cerulean reflecting brightly in the light of the rising sun. It seemed way too convenient that the sun had already begun shining, but there it was, and there was no denying it.
The sounds of shinobi nearby meant the chuunin were coming to collect Mizuki and hand him over to Ibiki. Iruka shuddered slightly at the thought of Konoha's top interrogator and his unnerving assistant, Anko, dealing with the traitor. The chuunin instructor turned back to the newly minted genin standing in front of him with a massive grin on his face.
"Head home and rest for now Naruto; I need to go grab Renji and explain the situation to Hokage-sama, though I have a feeling he already knows. You've more than earned a good sleep after this. But remember we're announcing the Genin teams at noon tomorrow so don't oversleep," Iruka said gently, almost like he was talking to his own son.
"Hai, sensei," Naruto saluted teasingly before he walked off back to the village.
Iruka rushed back to where he had left Renji, slumped against the base of a tree and groaning in pain. It wasn't ideal but it was the best they could manage when Naruto hastily made a Kage Bunshin which Iruka used a Kawarimi in conjunction with a Henge on. That rushed but effective maneuver bought them just enough time to keep Renji alive while Naruto took down Mizuki with the Tajuu variant of his new favorite jutsu.
Leaping through the tree branches, Iruka nearly slipped from his perch when he saw where he had left Renji. The boy was gone. There wasn't a trace of him left, other than the blood that had dried into the thick roots they had laid him against. But that wasn't the most intriguing part of what he saw. The entire tree had been burned with lava, Due to him being injured and not being in enough control of his chakra and his heightened emotions because of fighting, just melted the tree.