"Hah... Hah... Are you sure it's really Kai Uchiha?"
In the shadows of a distant valley near the border of the Land of Grass, Uchiha Obito knelt on one knee, gasping for air. His right eye was bleeding, the aftereffects of Kamui warping him into and out of battle.
Even with the aid of Hashirama cells through White Zetsu's body, Obito's chakra and ocular stamina were waning. His Mangekyō Sharingan was newly awakened—not yet fully mastered. Worse still, he had only one eye. Forcing Kamui beyond his limits was taking a toll even he hadn't anticipated.
"It's likely him," came the voice of White Zetsu, though he sounded hesitant. "Our other clones reported he fought off a squad of Kirigakure's Hunter-nin. That skirmish led to Nohara Rin being taken. Kakashi went ahead to rescue her… and Uchiha Kai showed up after defeating the Mist-nin pursuing them."
"Then… why is he wearing a mask?" Obito asked, his voice strained.
"He may be hiding his identity—or more importantly, hiding his eyes," Black Zetsu added, surfacing from the ground nearby. "The Mangekyō Sharingan is no ordinary dojutsu. You know its cost better than anyone. I don't know much about Uchiha Kai either, but he's dangerous. That much is clear."
Obito frowned. His memories of Kai were hazy—just a quiet, sharp-eyed kid from the Uchiha district. Polite, reserved... not someone he ever saw as a threat. But that made his hidden strength all the more unsettling.
As Obito stared toward the haze-covered forest, Black Zetsu watched him closely. The former Madara Uchiha had molded this boy carefully. Everything Zetsu and White Zetsu said was technically true—but carefully chosen. Just enough honesty to gain trust. Just enough ambiguity to sow doubt.
Obito had lost Rin. To him, it was like losing the entire world. His belief in Konoha, in comradeship, in the Will of Fire—shattered in one night.
Now, with nothing left to anchor him, Obito clung to the new dream Madara had offered: the Infinite Tsukuyomi. And with every loss, every lie he accepted as truth, he fell deeper under their control.
"You think we should expose him?" Obito muttered darkly. "If he wants to stay hidden, wouldn't unmasking him cause chaos? He could interfere with the plan."
"No," Black Zetsu replied at once. "Let him stay in the shadows. The less he knows about us, the better. He doesn't even realize you're alive—not truly. Let him believe whatever he wants."
"He's strong," Obito muttered, frustrated. "Too strong."
"Exactly. He's your best whetstone," Black Zetsu said. "A rival is useful—he'll push you to grow. But don't worry. His eyes won't last long…"
Meanwhile, deep within a ruined cavern—once the hidden base of Madara Uchiha—Uchiha Kai stood silently.
Ash and embers floated through the air, smoke curling around his black cloak. His breathing was calm, his Sharingan active. The half-destroyed White Zetsu corpse at his feet twitched once before going still.
"This time, it's a bloodbath," he muttered. "Let's hope Obito isn't completely insane yet…"
Kai had risked everything to raid this base. He suspected Obito was being manipulated—but he needed proof, and he needed resources. The twisted clone bodies, the traces of Senju DNA… it was all here.
He bent down, retrieving a severed left arm—Obito's arm, torn during a brief clash when Obito attempted to teleport away.
"Hashirama cells... and residual chakra signatures," Kai murmured. "You left in a hurry, Obito."
Kai's expression darkened. He wasn't interested in power for its own sake—but he needed strength to survive the plans that were now in motion. He'd seen glimpses of it. Rin's disappearance. Kakashi's movements. A masked man too strong to be a simple ANBU…
He took several sealed scrolls and stored the biological samples carefully. But just as he began placing explosive tags to destroy the cave, something caught his eye.
One of the stone benches, cracked by his Fire Release earlier, had broken open—revealing a hidden compartment.
"What the...?"
Kai lunged forward. Within the stone was a sealed scroll, yellowed with age—clearly old, but untouched by fire. He snatched it up and unsealed it just enough to confirm it bore Madara's chakra signature.
He immediately resealed it and made a clone.
"Get this back to the village. I'll cover our tracks."
The clone nodded and vanished.
Kai finished rigging the cave with fire-style traps. Then, as the last embers caught on the scrolls he had left as decoys, he turned toward the exit.
Behind him, a pillar of fire engulfed the cavern.
Outside, Black Zetsu and Obito watched the smoke rise into the sky.
"He destroyed the entire base," Black Zetsu said through gritted teeth. "That scroll... could've had Madara's research!"
Obito was silent. Deep down, he felt uneasy—but he masked it with cold detachment.
"We'll deal with him eventually," he said. "For now, let him hide."
"Let's hope," Black Zetsu murmured, "he didn't find too much…"