Overlaying her knowledge of the human anatomy, she analytically understands Sasuke's Chidori punched right through the false ribs eight, nine, and ten, and part of Naruto's stomach. Sakura gravely notes the specks and splatter of red on the floor, thinking, 'that's a lot of blood.'
Distastefully astonished, Kiba mutters what the other genin are thinking, "damn, Sasuke…"
"His own teammate," Chōji slowly voices in horrid awe, never in a million years thinking a teammate could do that to another.
Though Kurenai hides her rapidly devolving turmoil behind her glazed mask, her heart is beating painfully fast, and at the reverberating sound of Naruto's scream, she's stopped breathing. Her body overheats, her knees feel paper-thin, and her toned gut tightened to steel as she mentally screams, 'nonononononono!' Despite being a kunoichi who believes in village unity, especially among countrymen, her angry red eyes land on Kakashi, mentally yelling, 'you let this happen!'
After redirecting what would've been a strike to the heart, Naruto's weakened hand desperately grips Sasuke's bloody forearm as he screams till he's out of breath. With a face of unbridled anguish, his sweaty blond head falls forward, locking piercing blue eyes with Sasuke's three-tomoe Sharingan.
Through the salting spikes of pain drills continuously down to his twitching toes, Naruto's blood leaking mouth gasps, "you… really…"
"It's over," a stern-eyed Sasuke calmly asserts, roughly removing his arm from the bloody hole he created. He grips Naruto's neck as he comments, "you may have deflected my attack but you can no longer- NGGH!" Sasuke grunts as Naruto's jittery hand grips Sasuke's wrist before doubling then tripling in strength.
Within the dank depth of Naruto's seal, in the dark room of the flooded grand chamber, and before the tower-tall shoddy gates, Naruto grimly stares up at an impressively irate and growling Kurama. Feeling just as insanely provoked, Naruto extends two fingers to his orange-furry partner and Kurama chuckles. Red chakra then flows forward with purpose, enveloping a very willing Naruto in the seal as it does in the dueling chamber.
Kurenai was contemplating beating an apology out Kakashi when the atmosphere in the room suddenly spiked violently, nearly instantly fluctuating the displaced molecules in the air so hard the entire room forcefully heats with an odd blueish-white glow.
The audience is unprepared, shocked, and confused, however, none more so than Sasuke. The energy in the room quickly grows dark, poisonous, sinister, and before Sasuke could react, Naruto punches him meters away harder than he's ever been hit before, to the point Sasuke ignores the skin-scrapping pain of his body skidding on the ground tearing at his shirt, as well as hitting the wall, for the terrifying sensation radiating from his face, like his fractured skull and torn facial muscles were melting off.
Through his disorientation, Sasuke unleashes the full power of his cursed seal, turning his pale skin dark-gray, his ebony hair long light-blue, adding a black four-pointed star on the bridge of his nose, and sprouting wings in the shape of a hand. He hasn't practiced entering the third stage of the cursed seal, but Orochimaru explained enough for Sasuke's mind to figure it out on the fly. Fortunately, the throbbing pain to his face diminishes as more power swells within him, infusing more chakra into his shocked Sharingan as he beholds a slant-standing Naruto.
Naruto's blond hair whips ferally as the gaping red wound just below his left pectoral heals impossibly fast. The room's spectators all view Sasuke's blond and bloody opponent reform muscle mapped bone before searing skin sizzles and bubbles into place in seconds. All the while, chakra energy rushes around him so forcibly, it rips the zipper of his jacket open, revealing the wire body mesh underneath.
Recognizing the chakra, Kurenai along with the other Jōnin prepare to intervene before it's too late when their Hokage waves them off with a single raised palm. Kurenai isn't sure why her Hokage would allow this unnecessary risk to everyone in the room but her fear for Naruto immediately doubles.
"…I don't understand," Ino bemoans with a clear sniff, clearing the rolling tears streaming down the corner of her eyes. Looking from the suddenly demon-like Sasuke with wings clutching his wincing face, to Naruto as red chakra envelops every part of him, Ino asks anyone, "how…"
"What's going on," Shikamaru slowly asks his sensei in disbelief only to take note that Asuma has his chakra blades out sharpened with his blue chakra as he keeps his eyes focused on the stage. It's then that Shikamaru notices his sensei, Guy-sensei, and Kakashi-sensei are all in a defensive stance. Even the other Jōnin and the Hokage are positioned in high alert, as if expecting to enter the fight themselves.
Naruto hunches over as his power multiplies exponentially, visibly layering his form in red chakra, and unlike the previous occasion on the bridge against Zabuza, the shroud bubbles a long red tail as well. The tail whips hypnotically as his thrashing chakra super-charges the atmospheric pressure violently, disrupting the air, stone, dust, and ninja in the room with painful waves of itchy energy. The pressure in the atmosphere burns hotter around the feral blond, nearly making him glow as the floor and walls rattle, only becoming worse when a second tail begins to bubble and form, nearly suffocating those nearby.
"What's with this creepy feeling," Chōji yells, staring at his hands as he feels the oppressive oily energy pushing on his skin.
Watching Naruto with two tails and elongated ears made entirely of chakra, Ino commands to know from Sakura, "what's going on with Naruto?" There is no response Sakura can give as the gathered genin simply stare in unacceptable disbelief.
"That's… not possible," a thoroughly bewildered Sasuke utters.
The black slits within Naruto's red eyes glare mercilessly at the further enhanced Uchiha. Through clenched, sharper canine teeth, a feral chakra-covered Naruto growls a long-drawn-out sound, and though he's nearly delirious with the staggering amount of power surging ferociously through his system, his mind and focus are clear.
Naruto throws out a large red arm, causing a shock-wave too large for the small room, shoving everyone back. Sasuke jumps over the angry red hand. Not expecting another arm to shoot out from the previous extension, Sasuke's meaty wings flap him out of the way, only to be grabbed by the feet by another red hand before Naruto whirls him through the air like a ball at the end of a string and slams his teammate into the stone floor at the other end of the room, fracturing a three-foot radius of stone around Sasuke's battered body.
With an ear-piercing roar, the large room shudders in the unrelenting hot density waves bombarding everyone. Naruto pulls on the red chakra hand, explosively drawing Sasuke to him with all the abundant strength in him. The gray skin of Sasuke's bleeding face flaps like paper in a tornado before contorting around Naruto's iron fist as he's punched so hard, the last Uchiha rockets through the wood and stone wall to the room beyond.
After hearing a meaty crunch and snap in the same breath as heavy stone falling to the ground, and rolling rubble, the room stills. For many moments, all that can be heard from the stage below is the sizzling of Naruto's chakra heating the air and his low snarl.
For all who remember Naruto's antics, Naruto's grades, Naruto's thoughtless boasting… the chakra-covered genin below was such an impossible sight to witness. It was unthinkable to see the blond Dead Last of their class stand tall and dominant against the rookie of the year, the genius Uchiha Sasuke, yet, to deny it would be to deny reality and descend into delusion.
For most, it was like the game they've all been playing since their Academy day was suddenly outdated and boring, especially when Rock Lee asks his sensei, "Guy-sensei, are your sure Naruto-kun was the Dead Last of their class?"
Naruto huffs in mild amusement when Sasuke's shaky gray hand grips the broken stone wall and he slowly staggers through the hole and over rubble. He's hemorrhaging from his nose, mouth, swollen left eye, and unswollen right eye, sweating profusely, dirty, and his heavy breathing causes some twitching of his torso, likely from broken ribs. Naruto wonders if his teammate has a punctured lung but with three slow hand-seals, lighting erupts from Sasuke's left hand along with the sound Chidori is described after.
Naruto sprints faster than an exhausted Sasuke can physically react, cracking the stone floor with his every sprinted step and embeds his body-launching, overpowered fist into Sasuke's gut, instantly snatching Sasuke's left arm to keep the boy from flying away. Like a running dog chained to a stake, Sasuke grunts loudly as his withheld arm is dislocated by the explosive motion of his catapulted body.
Grunting loudly, the Uchiha grips his dislocated shoulder as his disheveled hair begins to return to its coal-black color, his gray dirty skin to its pale tone, and his single visible Sharingan deactivates. When Sasuke feebly tries to remove his arm, Naruto doesn't let go, and instead squeezes his forearm that much tighter, drawing a wincing grunt from the last Uchiha.