He couldn't be certain of the truth.
Based on his own experience, while there was a fundamental leap in power between the Sharingan and the Mangekyō Sharingan. It wasn't an overwhelming transformation in the physical sense, but even still, the difference between the two was obvious. Once a Mangekyō was used, even without any unique techniques, just the pure use of the regular dojutsu alone would be enough for others to notice.
Just now, Rēn had used genjutsu several times to defeat fellow clansmen. Shisui had been watching with his Sharingan the whole time, and yet, he didn't detect any unusual fluctuations in dojutsu output.
Normally speaking, even among three-tomoe Sharingan users, the power gap shouldn't be that vast. How had Rēn's dojutsu grown so strong in a three-tomoe state that he could completely overpower others with the same level of Sharingan?
The inability to explain it left Shisui deeply puzzled.
At this moment, the battle continued.
The Uchiha were a proud clan. Their pride didn't allow for surrender or concession. Even knowing they had little hope of winning, they would fight to the last moment.
"Earth Release: Rock Pillar Spears!"
"Fire Release: Phoenix Sage Fire Technique."
Seeing their comrades defeated, the remaining two did not act recklessly. They learned from the other's failures and, now fully aware of how formidable the Samehada was, changed strategies again. They gave up on taijutsu and switched to ninjutsu, doing everything they could to grasp the smallest chance of victory.
Fortunately, their heads were still clear. They didn't go all out with powerful terrain-changing jutsu like Great Fire Annihilation.
"Ninjutsu, huh?"
A pleased smile appeared on Rēn's face.
Among the three great disciplines of shinobi arts—ninjutsu, taijutsu, and genjutsu—what he was best at wasn't genjutsu or taijutsu, but ninjutsu. His innate skill, Mana Infusion (Flame), had elevated his mastery of Fire Release to the highest degree. That was the reason he had earned the title of Flame Demon.
"Fire Release: Great Dragon Fire Technique."
Rēn formed the Tiger seal with one hand.
In an instant, he refined a precise amount of chakra and exhaled. A vividly lifelike fire dragon with sharp horns took form in the air. It didn't fly straight; instead, like a fish swimming through the air, it curved around, using its massive body to effortlessly swallow the scattered phoenix flames coming toward it.
Next, the dragon crashed down onto the earth, obliterating all the stone spears that had risen from the ground. It even tore off part of the wooden floor and soil. Just as the surrounding onlookers prepared to step in to save the two men about to be engulfed—
The fire dragon suddenly spiraled in place and dissipated on its own.
"Amazing."
Uchiha An, the only female elder among the six senior council members, spoke involuntarily.
"Brilliant technique. Rēn, your Fire Release is nearly one-third as impressive as mine was in my youth!" Elder Homaru laughed heartily, clapping his hands hard as if applause alone could express his excitement.
"So cool! As expected of Rēn-nii."
Uchiha Hokuto jumped up. If Uchiha Ranzan hadn't been holding him back, the kid would've started dancing on the spot.
It wasn't just one or two people praising Rēn's perfect Fire Release. The Uchiha were all fire-style experts. Especially in this chamber, nearly all the jōnin were seasoned in fire-style jutsu. They understood better than even Mist shinobi just how refined Rēn's Fire Release was.
It had clearly transcended standard Fire Release techniques and reached a level of mastery where he could shape them at will.
Unless it was an S-rank technique, most Fire Release jutsu had already lost meaning in Rēn's hands. For example, the standard C-rank Great Fireball Technique could be scaled by Rēn from C-rank all the way to A-rank depending on his intent.
"So the Great Dragon Fire can be used like that? I've been trying to launch four dragons at once this whole time. I guess my mindset was too narrow. More doesn't always mean stronger…"
"So that's the Flame Demon?"
"Can any of you pull off something like that?"
"How could I? If I could use Fire Release like that, I wouldn't still be single."
"Get lost. Your love life has nothing to do with how flashy your jutsu is."
The conversation began to stray, but Rēn had already achieved his goal. The earlier genjutsu and taijutsu, combined with the now overwhelming Fire Release, had visibly shaken the room. Even the veterans in their forties and fifties started to feel their attitudes shifting.
Their hostility toward Rēn faded almost instantly.
This was the Uchiha.
A clan that revered power to its very core.
They prided themselves on their bloodline, their talents, their dojutsu, and above all else, their strength. And because of that, they respected those stronger than themselves. In front of a true powerhouse, age, rank, and seniority ceased to matter.
As the excited chatter of the clan continued,
The battle came to its conclusion.
"You lost."
Behind the two men stood two Rēns, each holding a short blade against their kidneys. One thrust would be fatal.
"When?"
The two turned their heads in disbelief.
"While your vision was blocked by the Great Dragon Fire," one of the Rēns answered with a smile.
"We lost. You… really are qualified to be so arrogant."
The proud Uchiha finally bowed their heads before another Uchiha.
They couldn't bring themselves to lie or deny the outcome. With so many watching, it would be shameful. And beyond that, the overwhelming defeat dealt by that incredible Fire Release had left a psychological gap too wide to cross.
This wasn't a moment to posture as old veterans.
The two sighed, carried their defeated teammates, and retreated to the chamber's left side. One of them had their Shackling Stakes Technique dispelled by Rēn. Uchiha Yashiro and the previously unlucky Uchiha Kōhei were also released.
But now,
Everyone clearly understood just how dangerous the Flame Demon was. No one dared speak rashly again.
"Anyone else wants to come and play?"
Rēn waved. Two water clones broke apart, turning into puddles on the floor. The chamber really needed repairs. Between Earth and Fire Release, the floor had been completely ruined. If nothing was done, the next clan meeting would need to be held against the walls.
His voice echoed across the chamber.
No one stepped forward. Four against one had already been shameful—and they'd lost. Rēn wasn't even breathing hard. Anyone else challenging him now would only embarrass themselves. No one wanted that.
Rēn waited around ten seconds.
When no one responded, he didn't push. Instead, he flicked his wrist, signaling the Samehada to retract its spikes.
Then,
He turned to the clan head, whose face was growing darker.
"If no one else wants to fight me… then let's get to the main issue. I, Uchiha Rēn, formally impeach the current clan head, Uchiha Fugaku, for dereliction of duty and repeated misjudgments. He bears direct responsibility for our current situation. From this moment on, he is no longer fit to lead the clan."
Rēn, riding on the momentum of victory, challenged Uchiha Fugaku head-on.