Naruto: I Can Upgrade My Techniques Infinitely

Boom!

Watching the plume of fire erupt behind them, Nara Kazuki's eyes gleamed with satisfaction.

Over the past few days, he'd been spamming the Great Fireball Technique relentlessly. While it hadn't quite reached its next mastery threshold, it had advanced the progress of its hybrid form—Great Thunder Fireball—considerably. Now it was just a hair away from upgrading. Once his Shadow Clones exhausted their chakra reserves, he figured the technique would be ready.

"Captain, why do you keep throwing out the Great Fireball Technique?" Shisui asked, his tone puzzled.

In his view, once a jutsu was learned, further repetitions were largely pointless unless one aimed to refine chakra control or seal speed. And even then, Kazuki's repetition seemed... excessive.

"Practice, obviously," Kazuki replied casually. They were still en route to their destination.

He had carved out three days to reach their target—by noon tomorrow, they'd be in position to rendezvous with the Konoha spy embedded in Iwagakure. If all went smoothly, they might even make it back early.

Itachi peered at Kazuki with mild curiosity, then glanced at his older brother. Shisui scratched his head, clearly itching to say something, but ultimately held his tongue.

After all, every shinobi had their own training style. Just like how some Konoha villagers had seen that one man with a bowl-cut relentlessly training his body without ever touching ninjutsu. Shisui had crossed paths with the guy a few times. Maybe Kazuki was just another eccentric in that mold.

After a while, fatigue began to creep into Kazuki's limbs, followed by a rush of memories—fragments from the training his Shadow Clones had undergone. Their chakra had been fully spent. And now, the Great Thunder Fireball Technique was ready for an upgrade.

Kazuki's pulse quickened.

It had been a while since his last jutsu upgrade. He knew better than to rush—it was getting harder and harder to level techniques now, and he'd noticed something else: the more complex the jutsu, the more skill points were required. For example, the Rasengan demanded an absurd 2,000 proficiency points for an upgrade. Completely bonkers.

Calling for a rest break, Kazuki opened up his jutsu interface and checked the available upgrade paths.

[Fusion Jutsu Is King]

Your Lightning Release and Fire Release techniques now synergize perfectly. When performing hybrid Lightning-Fire jutsu, total power increases by 300%, area of effect doubles, and chakra cost is halved.

[Reuse & Recycle—Sanitation? What's That? Customers Can't See It Anyway~]

Each time Great Thunder Fireball is launched and fails to hit a target, the fireball can be recovered and stored. Maximum storage capacity: Infinite.

[Lightning Release: Flame Demon Aspect]

An advanced evolution path for Great Thunder Fireball. Selecting this allows you to spend 30x chakra to replace the fireball with a unique jutsu: Lightning Release: Flame Demon Aspect. Unlocks further upgrade branches.

Three options. All overpowered. All headache-inducing.

Kazuki rubbed his temples.

The first choice was a blanket power boost to all Lightning-Fire hybrid techniques. Simple. Brutal. But hard to leverage fully, since composite jutsu weren't easy to create or master. To date, he'd only managed one—Great Thunder Fireball.

The second... Kazuki's expression twitched. That title definitely mocked some fast-food chain back in his original world. He remembered hearing about a scandal where a restaurant recycled uneaten mushrooms from customer plates and served them again.

Recycling leftovers. Reusing unsanitary food. Not a good look.

Still, the upgrade's effect was insane: an infinite-storage attack pool? That was busted. Even if the catch was that it only worked when the jutsu missed the target, Kazuki's imagination was already spiraling. He could fire off Thunder Fireballs daily, collect them for a year, then nuke a village solo with his personal fireball arsenal.

The only snag? What counted as a "miss"? If he deliberately fired wide, would that count? If so—yeah, this jutsu was broken. But if it only activated when a genuine attack failed to land... well, then it was a grind.

Still...

"And the third one... Lightning Release: Flame Demon Aspect?" Kazuki murmured, intrigued. "This is the first time I've seen a completely divergent jutsu evolution path..."

No clear description, of course.

Typical.

It was a gamble. But an enticing one. While the second option tempted him, Kazuki hadn't chosen Thunder Fireball's previous upgrade path just for fun—he was aiming for that elusive final branch.

"Alright," Kazuki muttered, committing.

He could always return and select the second one later via a reset point. After the Uchiha situation was dealt with, and once he had spare resources, he could revisit it.

With his choice locked in, a wave of knowledge surged into his mind.

He now understood the full mechanics: he could continue casting Great Thunder Fireball as usual. But by pouring in thirty times the chakra, he could morph the jutsu into Lightning Release: Flame Demon Aspect.

Thirty times the chakra.

Kazuki winced. If Kakashi tried this, he'd be face-down after three casts.

"…Man, I really want to test this," Kazuki whispered, his hands itching.

But they were still on a mission.

He sighed and reluctantly shelved the idea—for now.