Naruto: I Can Upgrade My Techniques Infinitely

"It hurts," the monster muttered as it clawed its way out from the forest of stone spears. It had once resembled a man—but no longer.

Now, its entire body burned with white fire. It had grown larger, jagged flame-forged spikes erupting from its body. Its head, a twisted mass of fire, still retained humanoid features—but barely.

The creature yanked out the stone spears embedded in its torso one by one, tossing them aside like twigs.

The surrounding Iwagakure shinobi instinctively took a step back.

"...Captain, w-what is that?" one shinobi stammered, eyes wide in terror.

After all, their team captain's favorite phrase had always been: "I've done more missions than you've had meals. There's nothing I haven't seen."

"I… I really haven't seen anything like this…" the Jōnin replied, his voice low and shaken.

Was it even human?

If it was human, why wasn't it bleeding when pulling out the spears—why was it just… burning?

Was this some new Kekkei Genkai?

He didn't know. But he knew what had to be done.

"Capture him!" the Jōnin barked, urgency in his tone. This strange enemy was far more valuable than the Konoha spy. That spy wouldn't yield much intelligence—but this… this ninja, this technique—

They had to crack open his mind. Extract the secrets of this jutsu.

Kazuki opened his mouth. He was in pain—real, unrelenting pain. And he was angry.

The last assault had pushed his Rage meter high enough to activate the enhanced phase of Flame Demon Aspect. His senses, his reflexes, his strength—all elevated. But the price…

He was out of chakra.

Or close to it.

The transformation had burned through nearly everything he had. At best, he could muster one last Great Fireball Technique. One more. Then he was dry.

But he'd succeeded in buying time. The plan had worked. All that was left was to hurl one final Great Thunder Fireball, trigger the body swap with his clone, and escape.

"Earth Release: Swamp of the Underworld!"

The ground beneath Kazuki softened, sucking him in like quicksand. At the same time, a massive stone slab began to descend from above, while earthen walls closed in from the sides.

They weren't trying to kill him. They wanted him alive.

Kazuki narrowed his eyes. "Ka-ton," he growled coldly.

"...You're telling me that the Konoha monster sent to extract the decoy lifted a Great Fireball the size of a house with one hand?" In the Tsuchikage's office, Onoki's brow furrowed as he scanned the report.

The shinobi standing before him was wrapped head to toe in bandages, skin scorched by fire.

Of the ten-man team sent, three chūnin had been killed. Two critically injured. The rest, all wounded. And not only had the Konoha spy escaped, they'd failed to capture the creature that attacked them.

"Yes, Lord Tsuchikage. I failed the village," the Jōnin admitted, bowing his head in shame. They hadn't even stalled the target long enough for reinforcements to arrive. It was a total failure.

"No matter. The decoy was already compromised," Onoki said, waving it off.

He studied the intelligence report again, eyes narrowing.

The spy had been exposed days earlier. After receiving word that Konoha had dispatched ANBU for extraction, Onoki had decided to crush them—send a message to Konoha and flex Iwa's might.

He'd deployed ten elite operatives and a Jōnin to lead them. Reinforcements were waiting in the wings.

But they hadn't even lasted long enough to stall.

The target got away. Left behind a Shadow Clone to delay them.

Infuriating.

Still, Onoki didn't care much for minor losses in manpower. What did concern him was the intel: the creature from Konoha.

"A man of fire. A burning monster. No blood..." Onoki tapped the scroll, baffled. "What is Konoha developing?"

He didn't have the answer—but he knew he couldn't let them continue unchecked.

"Put a bounty on any information related to this technique. Increase border patrols. I want a lockdown—no Konoha shinobi slipping through."

The creature had fled, yes—but they hadn't made it home yet. There was still time to strike.

If they could capture that strange ninja, maybe they could uncover some of Konoha's secrets. Whether it was a newly developed jutsu or some bizarre bloodline trait, Onoki wanted it.

Kazuki, for his part, had no idea that the Tsuchikage had personally taken an interest in him. Even if he knew, he wouldn't have cared—he was already on the move.

"Captain, were you fighting that whole time using a Shadow Clone?" Shisui asked curiously.

He and Itachi hadn't even needed to fight—they'd just escorted Kabuto away.

They'd been planning to regroup and assist, but Kazuki had reappeared ahead of them. Shisui nearly attacked him, thinking it was an ambush.

Luckily, Kazuki had immediately given their prearranged code word.

"Secret," Kazuki grinned, rubbing his arm with a wince.

He had thrown his final Great Thunder Fireball, drained the last of his chakra, and bailed—swapping with his Shadow Clone mid-fight. The clone had stayed behind to keep the pressure on and cover their escape.

Shisui rolled his eyes, but couldn't help being impressed.

Itachi, meanwhile, looked like he had stars in his eyes.

He'd seen Kazuki transform into the burning monster—and it was awesome. He wanted to learn it.

Kabuto was much calmer. His initial shock had faded quickly. Now, all he cared about was whether this mission's completion meant he could return to Nonō Yakushi. Maybe, just maybe… he could finally leave this life behind and live as a normal person.

"How do we get back?" Kabuto asked, frowning. "Iwagakure's definitely going to tighten security at the border."

They still had to cross multiple countries before reaching the Land of Fire.