Continued flashback
Naruto Uzumaki didn't know what to do. He didn't know what to say. His eyes followed the lifeless form of Sakura fall to the ground, almost gracefully.
Kurama could feel the pain, the hurt, the anguish of his host. It affected him too. The fox wanted nothing more than to destroy Naruto's enemies and protect his young host. So Kurama did the only thing he could do for Naruto in the moment. Thr fox gave the jinchuriki the rest of the Chakra he could muster on the inside.
"Naruto I'm giving the rest of my own Chakra for you to use, it's going to be a bit heavy, but try not to go past five tails. Your body will not be able to handle the strain. Besides, that boy won't be able to handle you in four tails mode." Kurama spoke firmly, "Destroy him Naruto, I need to rest."
Naruto barely registered the voice in his head, for his mind was numb with the sight of a dead Sakura still very fresh in his mind. What the jinchuriki did register, however, was the massive Chakra swelling up with him like an ocean. Growing one, two, three and finally a fourth tail, Naruto Uzumaki roared at the Uchiha standing in front of him.
Sasuke Uchiha's mind was a different story, he reveled in the kill of the pink hair kunoichi. He was lost in ecstacy until his sharingan registered a massive uptick in Chakra in front of him. He looked up to see a massive red fist flying at him. Sasuke veered to the right to avoid it, until witnessing a second branch of Chakra smashing him in the face.
Naruto Uzumaki was hell bent on annihilating his teammate, no matter the cost. Watching his prey fly from the physical contact, Naruto charged on all fours and leaped at the Uchiha. Sasuke formed his hands together and released a fireball at the fox, only to watch it glance off the jinchuriki. Sasuke then decided close combat might be more suitable, until another Chakra hand grabbed his leg, swinging him around like a rag doll.
Disoriented from the force, Sasuke could do nothing as his body was flung into a nearby rock, shattering his arm in two places and tearing a hole into his abdomen.The demon fox watched in joy as the Uchiha writhed in pain, gasping for breath. Naruto thought of something fun for the Uchiha to experience. He watched Sasuke get up slowly, wheezing.The fox threw out one Chakra hand, expecting Sasuke to dodge. Sasuke jumped up, his only good hand compressing his wound. The hand he dodged did the unthinkable, and split into multiple sharp blades, swiping at the airborne Sasuke.The Uchiha felt blades slice into his left leg, nearly cutting it off.
"Tch!" Sasuke landed awkwardly, leg shuddering and spurting blood. He steadied himself, thinking of ways to get out of this situation. He prepared to sprint hard, when a second hand came from beneath his feet, ensnaring the Uchiha. Sasuke struggled to get free as his opponent approached him with a maniacal grin. Sending his other hand out, Naruto grabbed Sasuke by the neck and held him still.
Sasuke choked for air, not registering the foot colliding with his hip until he felt a small pop. He felt the hand release from his neck and he attempted to stand. With one leg slashed open and the other now dislocated, all he could do was fall. And he did.
He screamed as his broken body fell to the ground, next to Sakura's. Staring at the broken form of his teammate, he realized what he had done.The curse mark, which had plagued Sasuke's mind, finally receded. Sasuke laid there, crying for the loss of his teammate. He watched Naruto approach him, form deteriorating again, absolute hate in his eyes."Naruto, I'm sorr-" Sasuke felt a foot enter his mouth as his face was kicked in.
Naruto growled in rage at his teammate, raising his foot again to strike the Uchiha's temple.
Sasuke coughed up some teeth on the ground, readying himself for another blow. He waited for a inevitable strike by closing his eyes until he heard another growl and a scuffle. Opening his eyes, he saw his teammate fall to the ground, a silver haired jounin pinning the foxes arm behind his back.
Naruto was livid as he struggled hard against the hold Kakashi had on him.
Kakashi watched the nine tailed's chakra recede from the genins body with his sharingan. Assessing the situation, he saw Sakura dead a few feet away, Sasuke with a broken and mangled body, and Naruto who went in a fox fueled rage. It all made sense to the Shinobi. He struggled to hold down the fox as his Chakra spiked again, this time Kakashi delivered a blow to the back of the foxes head, knocking him out cold.
Veering over to Sasuke, he looked at him sadly. The kid would spend a long time in the hospital. Kakashi tended to the young Uchiha and bandaged up the blood where he could. The broken bones and dislocation could wait.
"What happened here Sasuke?" The jounin asked gently.
"Naruto... he went berserk.. attacked us both, K-Killed Sakura..." Sasuke weeped.
"I see... good job surviving that Sasuke. Not many people could." Kakashi congratulated the crying genin.
He stood up, pulled a flare out of his pocket and threw it up into the sky. Seconds later the Hokage and several anbu appeared.
"Kakashi what the hell happened here?!" Exclaimed Hiruzen.
"The scene we have before us is one of sad circumstance, third Hokage. Naruto, who went out of control in his demon Chakra, attacked his teammates. Sakura and Sasuke put up a valiant fight against a jinchuriki but alas Sakura haruno has passed away. Sasuke held on as long as he could and fortunately will be alright." Kakashi spoke solemnly.
"How could Naruto's seal have degraded this much?!" One anbu yelled to no one in particular.
"We will have this discussion later. For now, we need to get Sasuke to the hospital and compile the truth in all of this." Kakashi said firmly.
At Konoha Hospital, 2 days later.
'How in the blue blazes did Naruto go into nine tails mode?' Kakashi thought, pacing outside his students hospital rooms.
'He hadn't shown any signs of communicating with the kyuubi, nor using its chakra. And how did a jinchuriki only break Sakura's wrist and neck?' He shook slightly at the thought of his precious student dying in such a cruel fashion.
Kakashi opened the door and walked in, witnessing both of his students. Sasuke was fast asleep, while Naruto, who bolted upright at the sight of his sensei.
"Kakashi-Sensei-" Naruto began before a hand silenced him, and a glare frightened him.
"Do you realize what you have done, Naruto?" Kakashi said with intense anger, the likes of which Naruto had never seen from his teacher.
Not about to be deterred, Naruto began again. "It wasn't me sensei, sasuke-" He was interrupted again, but this time it was a punch to the gut.
"Ugh!!"
'What the fuck is wrong with this guy?!' Kurama roared on the inside.
"Don't lie to me Naruto. You went out of control and nearly murdered both of your teammates. Sakura had started to care about you, Sasuke thought of you as his only friend. And yet you tried to kill them!" Kakashi roared at his disciple.
"I thought I had taught you the importance of teamwork and keeping your friends alive over the mission." Kakashi stated sadly, looking away from Naruto.
"Kakashi I didn't do it I swear!" Naruto pleaded, tearing up.
At that moment they both heard a groan, with Sasuke waking up in the adjacent bed. The Uchiha sat up looking at them both, fear becoming obvious as his eyes locked into Naruto's.
Getting out of bed, Sasuke ran for it, before Kakashi started to chase him.
"You are to stay here Naruto. ibiki and inoichi will test you mentally." Kakashi said coldly to his shaking student.
'Naruto what the fuck just happened!?' Kurama asked his host angrily.
'I don't know Kurama. I just don't know.' Naruto said simply yet sadly.
'But one thing is for sure Kurama, and that is we are going to kill that bastard. No matter who gets in our way.' Naruto spoke with hatred in every syllable.
Yes we are Naruto. Sasuke Uchiha is dead. He just doesn't know it yet.