~Soutarou & Fugaku POVs~
Fugaku said with confidence and a sinister smile, "it's over!"
Reaching the clone Fugaku struck through it and continued striking downwards at the ground with his ninjato lighting his hand up with fire nature chakra through pure natured chakra manipulation. The ground immediately collapsed and a groan was heard before a plume of smoke surrounded a confused Fugaku. Fugaku's eyes widened and he immediately rushed back as three clones shot jutsu at him.
'Wind Style: Air bullet!'
'Wind Style: Sword of Wind!'
'Wind Style: Violent Whirlwind!'
Without any choice Fugaku's sharingan swirled as he deftly avoided the incoming air bullets and stream of wind before flickering to the left to completely avoid the whirlwind. He flickered away and created a gap immediately before flying through hand signs and looking for the main body. Fugaku found another two clones each who were hidden with more chakra than the rest and did an extreme maneuver as he formed hand signs with one hand, while forming different hand signs with the other finishing the first jutsu he cast a 'Fire Style: Flame Whirlwind.' Then followed it up with an extreme A rank Sharingan Genjutsu that still required him to use hand signs due to his lack of mastery. Yet that was enough and in that moment both were revealed as clones forcing Fugaku back again as other clones peppered him with jutsu. At the same time the shadow clones Fugaku had created continued to struggle against Soutarou's due to number difference and lack of opportunity to cast dojutsu genjutsu. All of this combined meant that Soutarou's clones were able to break from their fights and pepper Fugaku's main body as well as gang up on Fugaku's clones, essentially making all the shadow clones from Fugaku a wastage of chakra.
Realizing his worsening position and lack of opportunity Fugaku dismissed his remaining shadow clones. He quickly pricked his thumb then proceeded to slam his hand down on the ground.
'Summoning Jutsu!'
A large majestic falcon with a massive wing span quickly took off with Fugaku on its back.
Soutarou who was hidden amongst his clones cursed, 'Isn't that Garuda? I don't have any long range aerial attacks. How am I supposed to deal with that? He can just snipe me and I used non-lethal poison so he can just wait me out…'
As if responding to his fears, fire balls started raining down on Soutarou's clones, some of whom began taking evasive maneuvers while a few remained and weaved signs together to use up their remaining chakra.
'Water Style: Wild Water Wave!'
'Water Style: Great Waterfall!'
The last clone however had much more chakra and it spewed out an immense almost Sea Release jutsu.
'Water Style: Great Exploding Water Colliding Wave!'
Soutarou on the other hand grimaced as the chakra expenditure of twenty something clones and only having around a twentieth of his chakra was beginning to catch up to him.
The last of Soutarou's clones with massive chakra began readying a jutsu while the others began firing off water styled attacks and wind styled attacks.
'Wind Style: Air bullet!'
'Water Style: Water Fang Bullet!'
All the while Fugaku simply responded with great fireball after great fireball evaporating the water once more. Which made gears turn in Soutarou, 'the quest said I have to use a self-created jutsu… that hasn't been made yet, is it worth a shot? I don't have a sharingan, but neither did Tobirama… that didn't stop him from being a genius. Let's do this!'
Steadying himself and nodding towards his last clone, Soutarou hid inside of the water and began closing his eyes and quickly created a hand sign and a seal appeared on his body.
'Lets hope this doesn't kill me.'
…
Meanwhile Soutarou's last clone flew through a number of hand signs before slamming its hand into the large pool of water that the other clones had created and shouted out, "WATER STYLE: WATER DRAGON BITING EXPLOSION!"
A pillar of water in the shape of a wide dragon shot towards the flying Fugaku at a break-neck speed shooting directly through the edge of Falcon's right wing and taking a significant portion with it just from the extreme water pressure before the water exploded outwards in every direction. The clone then used its remaining chakra placing its hand on the water and thinking to itself, 'While this move wasn't explicitly explained in his notes after 'creating' the rasengan I have enough mastery along with my water nature transformation to attempt this move.' Before the water dragon even hit the falcon Soutarou chakra flowed outwards as the water began to flow into the shape of a spiralling spear as the chakra began to rotate the clone noticed it was running out of chakra and just chucked into the air before shouting out in hopes of buying time, "WATER STYLE: HARD WHIRLPOOL WATER BLADE!"
Fugaku's eyes widened, as did Mito's, Hiruzen's, Setsuna's, Yuya's, and Tsunade's from the spectator positions all had one thought and thought only, 'Tobirama Senju/Evil Senju!'
Just to sell the act Soutarou's dispelling clone smiled wickedly and shouted, "THIS IS OVER YOU EVIL UCHIHA! THE SENJU WIN AGAIN!"
At that moment the mostly formed hard whirlpool water blade exploded near Fugaku sending his Falcon and him spiraling, a figure shot out of the water…
~Fugaku POV~
Never in his life had the talented son of the clan leader suffered a battle like this, every move calculated, every attack designed to counter, every method of attack he used either blocked before it did any damage, or thrown straight back at him. The entire fight made him feel disgusted and angry.
'I now understand why father said the second hokage was a genius beyond all measure, and why father said the Uchiha had no choice, but to join hands with the Senju… I detest you, Senju Tobirama and Senju Soutarou!'
Fugaku shook out his thoughts as his summon's wing was blasted with a massive spiraling water dragon that through sheer water pressure left the tips of Garuda's wing bare of feathers and flesh, before it exploded into a shining sea of tiny bullet-like water pellets.
His eyes began widening hearing the name of the jutsu uttered and before he could even shake off his stupor another even more ridiculous jutsu shot at forcing Garuda to spiral and lose control of its wings, throwing Fugaku into the mass of water below. Knowing engaging in close combat was a lost cause he whistled at the shaken Garuda to fly back towards him as fast as possible.
'Digusting senju!'
~Soutarou POV~
Unexpectedly Fugaku was forced off his summon and in that moment he shot towards Fugaku using water transformation at the tips of his feet along with monstrous strength a body flicker to force his body to speed up towards Fugaku. His ankles groaned, his thighs quivered, it felt as though all the muscles in his body were spasming. Reaching Fugaku who had long since noticed Soutarou's approach, Soutarou coated himself in a layer of water forcing himself through Fugaku's responsive jutsu.
'Fire Style: Dragon Flame Release Song'
Forcing him through the gaps of the oncoming dragon heads, Soutarou was seared by the heat before reaching Fugaku as a swirling ball of chakra formed in his hands Soutarou shouted out, "Rasengan!"
Slamming the orb into Fugaku's into a portion of Fugaku's lower midsection caused him to literally start rotating despite half of the jutsu not hitting him. Fugaku was flung backwards, but to Soutarou's dismay was caught by a damaged and struggling Falcon that slowly regained its altitude and began flying higher and higher.
~Fugaku's POV~
Fugaku saw from the corner of his sharingan a figure shoot out of the water, knowing he was low on chakra and could only afford a few more jutsu slowly formed seals waiting until Soutarou came into range before firing off one of the strongest fire style jutsu he knew, 'Fire Style: Dragon Flame Release Song.' What he didn't expect was for Soutarou to literally run through the gaps as even those were super heated by the extreme fire style, seeing Soutarou break through, Fugaku instinctively felt a chill and whistled louder hoping for Garuda to come and take him away. Seeing Garuda still a bit away he angled his body in order to dodge. What he saw instead was a swirling ball of chakra that reflected into his black eyes and shone in the now darkened environment.
Fugaku was blasted back, and he groaned in extreme pain as he felt several of his ribs break and his consciousness threatened to fade away. Yet, at that exact moment Garuda scoped him up and he forced him chakra out in a flimsy manner using yang chakra in a manner he had copied from medical ninja, but never refined and attempted to heal his wounds and expel as much of the poison as he could. Feeling his chakra drain to the point where he could no longer cast jutsu and only maintain Garuda's summon, Fugaku's expression darkened knowing he had lost. Yet despite his loss from his point of view, no one called the end to the battle….
~Spectators POV~
Mito, Mikoto, Kushina, Naori, Tsunade, Setsuna, Yuya, and Hiruzen all stared with awe. What they had just seen was a 10 year old boy using S-Rank water style and a self-created jutsu! Not only was the jutsu self-created it used no hand signs! A self created sealless jutsu at 10 years old! In the eyes of Mito, Setsuna, Yuya, and Hiruzen a formidable figure reflected… Though they had all thought it at the same time, now they seriously considered Soutarou… the inheritor of Tobirama Senju.
Mito on the other hand thought even deeper, 'He yelled Rasengan… is this the jutsu the system wishes to reward me after I complete the quest? Why would I need it if I can get it from Soutarou now?'
While Mito was flabbergasted, all the spectators felt that the two fighters were beyond their years in talent and ability, it's just in Soutarou's case it was so much more exaggerated.
Tsunade and Setsuna had forgotten their place as the proctors and hadn't noticed that Fugaku's chakra had fallen below the combat-able point.
~Soutarou's POV~
After using the seal to constantly force his chakra to draw in ambient chakra and casting the rasengan, Soutarou immediately moved back to his original intentions, forming three signs.
'While I've never practiced this… my lightning release was the one I focused the most on other than water release… I hope my understanding of this is right…'
Ox → Hare → Monkey… "Chidori!" At that exact moment Soutarou focused his lightning release to an extreme as a sound blaring across the entire. The chirping noise of a thousand birds, in fact it was so loud that Soutarou almost instinctively covered his ears, but he held back that urge focusing all of his chakra on his arm. At the same time almost all of Soutarou's vision blanked as the tunnel vision from the jutsu blinded him. Able to see and sense Soutarou simply raised his hand and forced the chakra upwards causing the jutsu to shoot upwards and lightning filled the skies as a massive lightning chakra head formed out from the clouds. Bringing back with it Soutarou's vision.
'I have no clue how this part of the jutsu works. I hope I aimed right…'