One Punch Man: Heroics Start with Dual Kamui

Shinji had just completed the first round of his training. That's right — only the initial phase. What came next would seriously ramp up the difficulty.

With another flash of Flying Thunder God, he vanished from the spire, the embedded kunai disappearing with him as he teleported back to W-City, still holding the blade.

There were plenty of cities on the system map he hadn't unlocked yet. His objective was clear: sprint across every remaining one using Body Flicker Technique, and embed a Flying Thunder God kunai into a precise location in each. If even one kunai missed its target, no matter how slightly, he would scrap the entire run and start over from the beginning. No breaks, no shortcuts, no mercy.

He dove back into his training with relentless focus.

[Alert! Host has arrived in V-City for the first time. Reward: 2 Points!]

[Alert! Host has arrived in U-City for the first time. Reward: 2 Points!]

[...]

By the time he completed the full circuit, Shinji had unlocked sixteen cities in total. But he still wasn't satisfied.

In the last city, his stamina had dropped dangerously low. His final kunai throw had hit the mark, but just barely. It embedded itself slightly off-center, close enough to register but too sloppy for his standards. He stared at the embedded weapon for a long moment, displeased.

Not clean enough.

Shinji didn't allow himself excuses. Not even minor mistakes were acceptable. His answer was simple: tomorrow, he would run the same route again, but cleaner, faster, and sharper. He wasn't ready for the real thing if he couldn't execute the final throw flawlessly after a full-speed cross-regional sprint.

But for now, he was completely spent. Time to rest.

As for the eleven kunai scattered across those cities, he wasn't worried about collecting them right away. The Flying Thunder God seals wouldn't fade. The only recorded case of a seal being forcibly removed was during the Fourth Great Ninja War, when Obito manually erased one. Outside of that, they were as good as permanent.

---

Back at the apartment door, Shinji unlocked it and stepped inside. The lights were on, and a familiar presence was draped across his couch like he owned it.

Saitama.

Sprawled out lazily in front of the television, he didn't even look away from the screen when the door opened.

Saitama's own TV had broken down recently, and he didn't feel like paying for repairs. So naturally, he started crashing at Shinji's place to watch shows. It was cheaper.

"Oh, you're back," Saitama said flatly, glancing over without much interest.

He noticed the glisten of sweat on Shinji's forehead and the weariness in his step. "You were training? You look wiped."

"Yeah. Just been dashing between cities," Shinji replied casually, tugging his coat off and letting it drop on the chair.

"Sounds kinda fun." Saitama's expression shifted — his eyes dulled, his mouth flattened, and he entered his signature "simple mode," staring at Shinji with that blank, deadpan look. "Can I tag along next time?"

Shinji stopped mid-motion, glancing back over his shoulder.

You? Tag along?

Saitama had no teleportation, no spatial awareness skills, and no sense of direction. If he came along, Shinji wouldn't be training anymore — he'd be babysitting a walking GPS error.

Saitama was bored out of his mind staying home all the time. Sure, watching TV and reading manga were his usual hobbies, and hero work was the one thing he genuinely cared about… but even he had limits. The routine was starting to feel stale.

What made it worse was how much he relied on news broadcasts to track monster activity. The media never bothered reporting low-level threats, so there were long stretches where he had absolutely nothing to do. No monsters, no chaos, just waiting.

"..."

Shinji suddenly froze mid-sentence.

Damn it. I slipped up.

He should've kept quiet about his training. Now Saitama was interested — and once he decided to tag along, tomorrow's session was almost guaranteed to devolve into a 1v1 sparring nightmare.

"…Sure. You'll probably beat me into the ground, though," Shinji said with a strained smile, already regretting it.

"Nah, I won't go that hard," Saitama replied casually, waving his hand like it was no big deal.

He was a little curious, though, about how Shinji was able to assess his real strength, but… too lazy to be curious.

---

The next morning, just after sunrise, Shinji got moving early.

His first order of business was retrieving the eleven Flying Thunder God kunai he had scattered across various cities during yesterday's endurance training. That part went smoothly. With all kunai back in hand, he returned home and brought Saitama up to the rooftop of their apartment — today's official starting point.

Saitama was already suited up and ready to go.

The yellow jumpsuit, white cape, red gloves and boots — the whole look was painfully low-budget, with its simple round buckle and old-school design. But that cheap outfit wasn't just some costume. It had been made for him by a small clothing shop owner who genuinely believed in Saitama's dream to be a hero. That belief stuck with him. From that day onward, this outfit became his only uniform — permanent and irreplaceable.

"Starting point is here, right? So where's the finish line?" Saitama asked, doing some basic stretches.

Shinji pointed across the cityscape. "Top of the Hoshino Grand Hotel in P-City."

"Got it," Saitama said with a nod.

Then he began warming up — and by warming up, that meant doing those awkward old-school elementary school exercises. He swung his arms back and forth, bent sideways with exaggerated form, and twisted his waist while humming a totally off-beat rhythm.

After a few seconds of his bizarre prep routine, he looked over with that familiar clueless expression. "Alright, I'm ready. Let's go."

"Three…" Shinji began counting down.

"Two…"

"One!"

And with zero, both of them launched forward.

Shinji disappeared in a flicker of movement, his body vanishing into a blur as he activated Body Flicker Technique.

Saitama… was just being Saitama.

With his arms thrust out in a full Superman pose, he rocketed off the rooftop like a human missile. It looked like a flight, but he wasn't flying — he was just bouncing through the air with leg strength alone. One small push at half power was all it took to launch him forward at terrifying speed, and he vanished over the horizon, leaving nothing behind but wind turbulence and Shinji's rapidly shrinking confidence.

Honestly, Shinji could've cheated.

He had already marked P-City with a Flying Thunder God seal, so all it would take was a flick of his will to teleport straight to the finish line and beat Saitama there with ease.

But he didn't.

Because this wasn't about winning. This was training — a test of stamina, technique, and focus. And besides, losing to Saitama? That wasn't even remotely embarrassing.

So even after being left in the dust miles behind, Shinji kept going at his own pace. He repeated the same pattern from yesterday's training — dashing from city to city, launching kunai with precision at carefully chosen targets in each new location. Only this time, everything felt different.

Smoother. More efficient. Sharper.

His movements were cleaner, his momentum steadier, his transitions between Body Flicker bursts almost seamless. Kunai flew from his hands with greater precision and less wasted effort. Even his posture while moving had improved. It wasn't just about speed — it was control. His body was working in perfect sync with his mind.

By the time he reached the final city — P-City — he still had stamina left. No trembling muscles, no labored breathing, no mental fog. It wasn't because his reserves had magically improved overnight. He had simply moved better. His improved execution reduced the overall strain on both body and mind.

Then he reached the top of the Hoshino Grand Hotel.

And froze.

Saitama wasn't there.

What?

That made no sense.

He hadn't seen so much as a glimpse of him since the initial launch. Saitama should've arrived ages ago — probably even had time for a nap. Or maybe he got bored waiting and already left?

Just as the thought crossed his mind, the system chimed.

[Alert! Host has defeated Saitama in the speed challenge. Reward: 100 Points!]

Shinji stopped breathing for a second.

"…I won?"

He stared at the empty rooftop in disbelief.

How?

Where was Saitama?

---

Meanwhile, in some random city nowhere near P-City, Saitama landed on a rooftop and blinked at his surroundings.

"I dunno, man."

Yep. You guessed it.

He was lost.

As previously mentioned: Saitama had absolutely zero sense of direction.

After takeoff, instead of heading toward P-City, he launched into the sky with his usual power... and completely overshot the target. One jump — just one jump — and he landed in the farthest possible place from the finish line.

A-City.

Now, standing alone on an unfamiliar rooftop, he scratched his head and looked around helplessly.

"Man, this is bad… I think I'm lost. Not even sure which direction I'm supposed to go now…"

He let out a defeated sigh, his expression as blank as ever, and glanced up at the sky as if it would offer answers.

---

Back in P-City, Shinji stood silently on the rooftop, slowly piecing together the truth.

There was only one possible explanation for his win.

"…Right. I totally forgot he's a walking GPS error."

It was so obvious in hindsight. Shinji instantly regretted not tagging Saitama with a Flying Thunder God seal before the challenge. If he had, tracking him down would've taken seconds.

But now?

Now he had no choice.

He pulled out his phone and dialed.

Somewhere deep in "Mystery-City-X," Saitama had just started debating whether to bounce in a random direction when his phone buzzed. He checked the screen and picked up immediately.

"Yo?"

"Shinji here," Shinji said flatly.

There was a pause on the other end.

"…So… I think I got a little lost."

Saitama's voice was sheepish, like a kid who wandered too far at the mall.

Shinji closed his eyes and dragged a hand down his face.

Of course.

---

"Seriously, I am really bad with directions. Man, it is just embarrassing." Saitama was at a loss for words before glancing at the person next to him. "Isn't that right, Mr. Mysterious man with green hair and swords?"

Zoro widened his eyes for a moment, then let out a long sigh. "Yeah…"

They both tilted their heads back, looked up at the sky, and sighed in unison.

===

Please vote for Bonus Chapters.

500 Power Stones = 5 Bonus Chapters

1000 Power Stones = 10 Bonus Chapters