Sasori of the Red Sand's plan was solid in theory, but its success depended on one crucial factor, Obito.
They needed to trap Ryūjin within a confined space.
If Ryūjin simply phased out of the poison gas, then no matter how lethal Sasori's toxins were, they would be useless.
That was why Sasori had handed Obito the antidote beforehand. From the very beginning, the plan required Obito to restrain Ryūjin while the poison did its work.
Obito understood this perfectly.
At this point, he had no better option.
Still, there was one concern.
"The Flying Thunder God Technique is something even I can't stop. He buried some Flying Thunder God kunai in the sand earlier. We need to find them first."
His expression darkened slightly.
If the kunai were visible, he could deal with them during battle. But hidden beneath the sand, they were far more troublesome.
Sasori, however, remained calm.
"No need to worry about that."
As he spoke, the sand around him began to flow like water. Several Flying Thunder God kunai emerged from within it.
During the earlier battle, Sasori had not been idle. While observing Ryūjin, he had secretly used his Magnet Release Iron Sand to gather every kunai buried in the area.
Obito wasted no time. His Kamui activated, and the kunai vanished into his dimension.
"I have already checked the entire battlefield with Magnet Release. Aside from these, there are no more Flying Thunder God kunai."
Sasori's tone was firm.
His control over sand allowed him to sense even the slightest disturbances across the ground. Locating hidden weapons was well within his capability.
"Well done. I'll hold him off. Find your chance."
Obito pocketed the antidote and disappeared with the Body Flicker Technique.
Clang! Clang!
The battlefield erupted again as metal collided rapidly.
Obito engaged Ryūjin once more, but the difference this time was overwhelming.
Ryūjin remained in Sage Mode.
His strength had surged to another level entirely.
Obito was forced on the defensive, barely holding on.
Without Kamui and the Rinnegan, he would have been defeated countless times already.
"This is ridiculous… he's been fighting this long and still isn't slowing down. Does he even run out of chakra?"
Watching from the shadows, Sasori grew increasingly wary.
What he did not know was that Ryūjin's chakra had long been heavily depleted. Unlike Obito, whose body was enhanced with White Zetsu cells, Ryūjin only possessed the reserves of a normal jonin.
The difference lay elsewhere.
Ryūjin could continuously draw chakra from the Tailed Beasts sealed within him.
He was, in every sense, a perfect jinchūriki.
There was no resistance, no instability.
The Tailed Beasts cooperated completely, allowing him to replenish chakra seamlessly without even forming a visible cloak.
And because Obito's plan revolved around the Tailed Beasts, Ryūjin had no intention of revealing this advantage.
"Obito's about to collapse," Sasori muttered.
He could not wait any longer.
With a flicker, he joined the battlefield.
Two puppets appeared before him, guarding against Ryūjin's terrifying dōjutsu. Then, he summoned the Third Kazekage puppet.
This time, however, he did not rely on Magnet Release.
Click, click, click.
The puppet's arms split apart, multiplying into hundreds, then thousands, each tipped with sharp blades that lunged toward Ryūjin in a relentless barrage.
The sheer volume rivaled techniques like Hidden Shadow Snake Hands.
Ryūjin glanced at him briefly, expression unchanged.
With a casual motion, he summoned sand to block the attack.
"Shinra Tensei!"
Obito's voice rang out.
A powerful repulsive force surged outward, knocking the sand off course and creating a gap in the defense.
Hiss! Hiss!
Dozens of blades slipped through and pierced toward Ryūjin.
He phased instantly.
The blades passed harmlessly through him and stabbed into the ground behind.
At that exact moment, a thick cyan gas began pouring out from the puppet's arms.
Poison.
"Uchiha Flame Formation!"
Flames erupted as a barrier rose around Ryūjin, sealing him inside.
The space within quickly filled with toxic gas.
"Got him."
Sasori's eyes lit up.
Obito allowed himself a small smile.
All the Flying Thunder God kunai had been removed. Ryūjin was trapped.
He could only rely on his phasing ability to survive.
But Kamui had limits.
Once that limit was reached, the poison would finish him.
A perfect plan.
Inside the barrier, Ryūjin looked around, mildly surprised.
"Uchiha Flame Formation…"
He recognized it immediately.
A powerful sealing technique, one that could even withstand blows from the Eight-Tails.
Breaking it head-on was pointless.
Not that he needed to.
He prepared to teleport, then paused.
His expression shifted slightly.
The kunai he had left outside were gone.
"Looking for these?"
Obito's voice carried a hint of satisfaction.
"For once, things went your way," Ryūjin replied calmly, almost amused.
Then his gaze sharpened.
"But if I want a marker, I'll just make one."
Swish.
He vanished.
In the next instant, he reappeared outside the barrier, standing calmly across from them.
Sasori's voice turned sharp.
"That's impossible. I checked the entire battlefield. There were no kunai left."
"There weren't," Ryūjin said, tone indifferent, "now there are."
He had already prepared for this.
A Shadow Clone had been hidden from the start, waiting underground.
The moment the original markers were removed, the clone moved into position with a kunai in hand.
Simple.
Effective.
Obito and Sasori both fell silent, their expressions darkening.
Without a way to counter Flying Thunder God, everything they did was meaningless.
"Sasori," Ryūjin said, turning his gaze toward him, "you should've stayed out of this."
His voice carried no anger, just cold certainty.
Then he moved.
In an instant, he closed the distance.
Sasori reacted immediately, unleashing a barrage of Iron Sand attacks, needles, spears, crushing blocks.
None of it mattered.
Ryūjin phased through everything and continued forward.
The gap closed rapidly.
Sasori felt it then.
Real danger.
"Damn it…"
Obito's expression tightened.
If Ryūjin got close with a clear line of sight, Sasori would not survive. Whether it was Kamui or Amaterasu, he had no defense.
Sasori knew this too.
His mind raced.
Nothing worked.
Nothing stopped him.
"…Then I'll use it."
His decision was firm.
The final scroll.
The mechanisms on his back shifted. The fourth scroll activated.
His chakra threads vanished, replaced by something different, pale and unsettling.
At the end of those threads was not a normal puppet.
It was a shadow.
A ghostly, illusory form.
At that exact moment, Ryūjin broke through the last layer of defense and appeared beside him.
He moved to activate his dōjutsu.
The shadow lunged.
Ryūjin hesitated for the briefest instant.
He had never seen anything like it.
Then it struck.
The shadow passed through his body.
And entered his soul.
A sudden, overwhelming sense of danger exploded within him.
"…A soul attack?"
For the first time in a long while, Ryūjin felt genuine shock.
Since gaining the Sign-in System, he had obtained countless powerful abilities. Nothing in the shinobi world had truly threatened him.
Until now.
An attack that bypassed everything and targeted the soul directly.
Even he had not expected this.
"…You've got to be kidding me."
But the shock did not last.
His eyes shifted.
The Sharingan transformed into the Rinnegan.
He reached out and seized the invading soul using the power of the Human Path.
At the same time, golden sand spread outward, blocking all lines of sight.
Obito and any hidden observers would see nothing.
Sasori's eyes widened in horror.
"That's impossible…"
His final puppet was a soul construct, something that should not even be graspable in the physical world.
Yet Ryūjin held it.
As if it were nothing.
As if even the boundary between soul and reality meant nothing to him.