In Naruto with the Flame-Flame Fruit

From here on out, the rest of the battles had nothing to do with Kiyosuke. He had already secured his promotion to Chūnin.

Unfortunately, both Kurenai and Asuma weren't as lucky. They each lost to their respective opponents and would have to try again in the next Chūnin Exams.

Out of the fifteen available spots, Konoha only saw Kiyosuke promoted. The rest were allocated to other villages. It was a diplomatic gesture—Konoha earned high praise for it. To maintain good relations, some of the selection was "adjusted" behind the scenes.

But none of that mattered to Kiyosuke anymore.

...

Inside Orochimaru's laboratory

"I've thought of a way to enhance my physical strength and speed," Kiyosuke said.

"Oh?" Orochimaru set down the test tube in his hand and looked at him with interest. "Let's hear it."

"I want to generate fire inside my body and circulate the heat it produces to create internal energy. I could then harness that energy to strengthen my body." Kiyosuke continued, "It's still just in theory, but I think it might work."

The idea had come to him when he recalled a manga character with a similar power. He figured it was worth testing.

Orochimaru pondered for a moment before responding,

"In this state, your body would become solid—tangible. Meaning, even if you succeed, you'd lose your flame form. After all, you're circulating fire internally, so only a part of you would remain in a flame state while the rest would revert to flesh. That would leave you vulnerable. Not to mention, if the experiment fails, it could burn out your body entirely."

As expected of Orochimaru—he immediately identified the weaknesses just from Kiyosuke's explanation.

"True," Kiyosuke admitted. "But if I can quickly switch between forms, I should still be able to access the flame state as needed."

"And how do you plan to do this?"

Orochimaru couldn't offer guidance. He had no experience in this kind of technique.

"I'm not sure yet. I'll just try and see. If I circulate the energy the same way we refine chakra through the meridian system, that might work." Kiyosuke patted his chest confidently. "I've got a good feeling about this."

Though honestly... it didn't sound all that reliable.

He sat down cross-legged, closed his eyes, and focused on sensing his chakra. He began converting it into fire, dialing down the temperature—too much heat would burn through the meridians. No room for recklessness.

Orochimaru, still thinking, spoke up: "Try concentrating the thermal energy in one spot, then release it in a burst."

Kiyosuke followed the suggestion. As the temperature rose, his skin flushed red. A strange energy began to stir, but just as he prepared to circulate it—poof—it vanished.

Opening his eyes, he said, "It didn't work. The heat couldn't be stored."

After describing the sensations to Orochimaru, the latter said,

"Try again. This time, direct the heat toward your heart and let it spread through your arteries to the rest of the body."

"That sounds kind of dangerous. Let's use a shadow clone."

He decided the clone could take the risk first.

He formed a clone and instructed it to follow Orochimaru's method. Not long after, the clone's skin turned red—then exploded.

When the memory returned to Kiyosuke's mind, he said,

"The clone rushed it. Too much heat gathered in the heart before it could circulate. The heart couldn't handle the load and blew up."

"Go slower this time."

The clone sat down and made another attempt—another failure. This time, the temperature got too high and scorched the blood vessels.

The third try...

It was finally a partial success.

The build-up and temperature were kept within acceptable limits. Kiyosuke did get stronger, but not nearly as much as he had hoped. And due to physical constraints, the form couldn't be maintained for long. Worse, the added heat heightened his skin's sensitivity—pain reception multiplied several times. Attacking an enemy in that state was like trading equal blows: injure the enemy, injure yourself just as much.

"This technique is pointless."

Orochimaru said, "If the result isn't worth the power, and it places such a burden on the user, then it's a failure. Kiyosuke-kun, there's no need to pursue this jutsu further."

Even forbidden jutsu—which often carry a steep price—usually come with immense power. But this one? It brought damage without any real benefit.

"It's useless," Orochimaru concluded.

"I understand. But... I have another idea."

Orochimaru's eye twitched slightly. What crazy notion had his student come up with now?

"Your earlier suggestion—to focus the heat in a single point—I think that could work. If I concentrate the flames there, I might be able to create a more explosive burst of power," Kiyosuke said confidently.

After considering it for a moment, Orochimaru nodded. This new concept seemed far more feasible.

"You can try."

"Alright." Kiyosuke, full of motivation, clenched his fist. Flames ignited around it as he channeled chakra, making the fire burn even more intensely.

"Fire Fist!"

He drove his fist into the laboratory wall.

Boom!

A thick pillar of fire burst from his knuckles, dazzlingly bright, punching through several walls in a row. You could even see the scenery outside—and in the distant forest, several trees had been felled and were now ablaze.

Orochimaru's eye twitched again, this time with a noticeable twinge in his gut.

Still, he gave his assessment: "Not bad destructive power. What about the chakra cost?"

"A bit more than the chakra used to detonate the clone," Kiyosuke replied, visibly excited. Which meant that if used in battle, it could be a one-shot finisher.

"Acceptable," Orochimaru nodded. "Impressive damage output. Now go put out the fire and fix my house."

"Huh?!"

"What's that look for? You broke my lab, didn't you? This isn't some Konoha training ground where you can throw around jutsu at will. If you can't fix it, you'll stay and help me with my experiments tonight."

"I'll fix it! I swear!"

Kiyosuke immediately promised. No way he was going to stick around for Orochimaru's experiments—they were way too gross.

Sure, he could learn a lot, but those experiments always left him nauseous. The next day, he'd barely have an appetite. He could eat, but barely anything.

"Then get to it."

Orochimaru shook his head. He was more convinced than ever that he needed another apprentice.

This one was trouble. Talented, yes—but not suited to inherit his legacy. And beyond that... the boy was always wary of him.

He could see it clearly—Kiyosuke was afraid of him. Was it because of the past experiments?

After all, he had used Kiyosuke as a test subject before. That likely left some bad memories. And with no parents, the boy was more sensitive to the world around him.

Oh well. Back to the experiments.

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Pls Drop some Power Stones

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