One Punch Man: Heroics Start with Dual Kamui

"The boring lecture is finally over."

Saitama walked down the road with his hands in his pockets, heading home.

Meanwhile, Shinji was checking the Hero Association's official website on his phone. He found that Saitama's profile had already been added to the hero registry.

He was now officially the 17th S-Class hero, ranked last among them, but still in the top tier.

Shinji scrolled down further and spotted himself ranked 56th in the B-Class.

He mainly wanted to check if the Association's executives had finalized his hero codename.

B-Class, Rank 56 — [Kamui]

Shinji let out a small breath of relief. Thankfully, they'd gone with his suggestion.

If they'd actually slapped him with something like [Red-Eyed Man], he would've seriously considered quitting on the spot.

"My hero codename's been approved. You'll be getting one too soon, Saitama," Shinji said.

"Hero codename? What's that all about?" Saitama asked, tilting his head.

"It's a name unique to each hero, usually based on your abilities or appearance," Shinji explained. "For example, the one they were originally going to give me was Red-Eyed Man."

He pointed at his Sharingan as he spoke. Obviously, the Association executives had come up with that name based on his eyes.

"Why do you say 'originally'?" Saitama asked curiously.

"Because I requested a change. They eventually approved it, and now my official codename is Kamui," Shinji replied.

"Ohhh..." Saitama nodded, then muttered, "So in my case, would my codename be something like Caped Baldy?"

Shinji paused for a moment. "...There's a good chance."

"That sounds awful. If it really ends up being that, can I apply for a change too?"

Even though Caped Baldy did technically describe Saitama well, he was particularly sensitive about the "bald" part and not thrilled about being called that.

In fact, later on, Saitama joined the Hero Name Victims Association, protesting with a megaphone outside the Organization's headquarters and demanding an apology, which showed just how much he hated that name.

"You can try. I can't say for sure," Shinji said with an awkward smile.

Most likely, Saitama's codename would be "Caped Baldy" again.

The only reason Shinji probably got away with changing his was a bit of luck.

When he had just gotten promoted to B-Class, his hero codename hadn't been finalized yet. Red-Eyed Man was likely just one of the options being considered.

And just as the execs were still undecided, Shinji sent in his suggestion. Too lazy to brainstorm more, they just approved it.

That's how most of the Hero Association's higher-ups operated — disorganized, lacking in leadership and competence, and many were involved in some pretty shady stuff too...

"Whatever. I'll deal with it later," Saitama said, no longer interested.

Right now, all he wanted was to go home, lie down, and read some manga.

---

During his free time, Shinji decided to test out the Body Flicker Technique. He had acquired it as a system reward, and like all his previous rewards, he instantly mastered the technique the moment he received it. No training was necessary to understand it, but mastery and practical skill were different things entirely.

If he relied solely on the baseline version of Body Flicker, the same technique nearly every shinobi in the Naruto world could perform, it wouldn't do much for him in real combat.

So he practiced.

Following the method outlined in the system interface within his mind, Shinji focused his mental energy and used it to stimulate his physical body, enhancing his speed. Normally, Body Flicker was powered by chakra, but the system had automatically modified it to draw from his mental energy instead. It worked differently, but the core concept remained the same — vanish from one spot, reappear in another, faster than the eye could follow.

He gave it a test.

With a focused thought, Shinji disappeared from his position and reappeared a few meters ahead.

"The speed's decent… but still not enough," he murmured, narrowing his eyes in analysis.

Very quickly, he identified two major factors that limited the potential of the Body Flicker Technique: physical attributes and mental energy strength. On top of that, repeated training improved fine control and precision — both of which were vital. After all, in the hands of an elite shinobi, even a basic Body Flicker could turn into a terrifying combat technique.

He opened his system panel to take stock.

[Host: Shinji]

[Age: 20]

[Status: Human, B-Class Rank 56]

[Abilities: Dual Kamui, Flying Thunder God Technique, Body Flicker Technique]

[Weapon: Crimson Night Blade]

[Physique: 75 (+ Hashirama Cells ×2)]

[Points: 41]

[Point Store (Lv1)]

(AN: I have no idea where this 'Crimson Night Blade' is from. If you know, mention in the comment.)

With 41 points available, Shinji decided to save them for now. Better to hold off until he had a clearer picture of what he needed.

Next, he began practicing how to chain Body Flicker with Flying Thunder God, while also using the opportunity to unlock more locations on the system map. But before he could begin long-distance teleportation, he needed to replenish his supply of kunai.

[Alert! The host has exchanged for "Fourth Hokage's Kunai ×10." Points deducted: 1. Remaining Points: 40]

With just 1 point, Shinji obtained ten special kunai — exact replicas of the iconic tri-pronged blades used by the Fourth Hokage, Minato Namikaze.

He carefully etched the Flying Thunder God formulas onto each kunai. As he channeled his chakra into the weapons, the handles began to glow faintly. The Flying Thunder God seal shimmered beneath an overlay of Kamui's sigil, the two spatial powers pulsing in perfect synchrony.

Once everything was ready, he launched into training.

Starting from Z-City, he employed a simple yet rigorous method: move using Body Flicker, then throw marked kunai at distant, narrow targets — like the jagged tip of a radio tower in a neighboring city or a single sea rock protruding above the waves. Doing so while flying through the air at high speed demanded intense reflexes and sharp hand-eye coordination.

Minato could do it effortlessly. He had honed such techniques to the point of perfection, mastering high-speed multitasking during battle and embedding markers on key targets in real time. But Shinji was just starting down that path. He had neither Minato's experience nor his legendary intuition, so he had no choice but to rely on relentless practice.

He surged forward, tearing through the sky with the Body Flicker Technique. Afterimages trailed behind him, his figure flickering with speed that still fell short of invisibility, but only just.

Up ahead, a target came into view: the spire of a skyscraper in the distance.

Shinji flicked his wrist.

The kunai launched forward, spinning with surgical precision. With the help of his Mangekyō Sharingan, his spatial awareness and predictive accuracy far exceeded normal human limits — even without formal training in throwing weapons, his aim was exceptional.

Thud!

The kunai embedded itself cleanly into the very tip of the tower.

"Perfect," he thought with satisfaction.

Moments later, he passed over the boundary into W-City.

[Alert! First time entering W-City. Reward: 2 Points]

Without slowing down, Shinji activated the Flying Thunder God Technique. In the blink of an eye, his figure vanished from the sky and reappeared atop the tower, standing silently with one foot balanced on the embedded kunai, his coat fluttering in the wind as he overlooked the sprawling city below.

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