One Punch Man: Heroics Start with Dual Kamui

"..."

Dr. Genus didn't answer. He just stood there, frozen. That silence was more telling than any words. It wasn't just a moment of doubt. This was full-on despair, the kind that sinks deep into your bones. Everything he'd built, everything he thought he knew. It had all come crashing down.

A red-eyed teenager who could summon a giant spectral warrior. A bald man who wiped out his most powerful creation with a single punch. These people defied logic. They defied science. They defied him!

His legs gave out. He dropped to his knees, trembling.

Maybe the world didn't need to change. Maybe he was the one who was wrong all along...

"Master, aren't we going to deal with him too?"

Genos asked quietly, glancing at the direction Dr. Genus had stumbled off to.

"No need," Shinji replied without looking back. He didn't explain. Just kept walking.

There was no need to say it out loud. What had happened today was more than enough to break the man. He'd probably abandon science altogether. If anything, Shinji figured he'd be selling takoyaki at a street corner before long. Killing their hope and letting them live is far crueler than killing them.

"Understood..." Genos didn't question it further. He simply followed behind his teacher in silence.

On the way back, Shinji took a few quiet moments to check the condition of his body.

As expected, using the third stage of Susanoo had taken a toll on him. Just summoning it for a short time had left a lingering discomfort in his muscles. The strain wasn't something he could ignore.

He definitely wasn't ready to attempt the full-body version. Not unless something changed.

To use the third stage freely, his body needed either a stronger concentration of Hashirama cells... or the Eternal Mangekyō Sharingan. Without one of those, it wasn't sustainable.

He considered both options. The Hashirama cells might be attainable with enough experimentation. But the Eternal Mangekyō... that was a problem.

Obito didn't have any siblings. And without a blood relative who also had the Mangekyō, fusing to achieve the Eternal form was impossible. Well, without a system at least.

…

Meanwhile, Saitama barely managed to make it to the supermarket in time for the big sale.

Shinji had already gone home.

Genos, on the other hand, had returned to his own place.

Shinji was planning to swing by the Hero Association to report his latest monster kill, phone in hand. But when he turned on the screen, he was met with a wall of unread messages, all from Lily.

Apparently, she hadn't taken his silence well.

After sending three messages with no reply, she followed up with three angry emojis, each one more steamed than the last:

[૮₍ꐦ-᷅⤙-᷄₎ა]

[૮₍ꐦ-᷅⤙-᷄₎ა]

[૮₍ꐦ-᷅⤙-᷄₎ა]

Then came the message that caught his attention: she said he had joined the [Blizzard Group].

Shinji stared at it for a moment before slowly replying with a single question mark.

[...?]

Seconds later, the app showed that the message had been read.

Almost immediately, Lily fired back.

[Lily: You finally replied! Do you never check your phone?!]

[Shinji: I was dealing with something earlier. Obviously, I couldn't check it. And who told you I joined the Blizzard Group?]

[Lily: Obviously Lady Fubuki! Why? What's wrong?]

[…] Shinji responded with an ellipsis, then paused.

He hadn't agreed to join the [Blizzard Group]; he was sure of that. But if Fubuki told Lily he had, then she clearly had no intention of letting him go. She'd just decided on her own and told everyone else he was in.

That woman…

[Shinji: Let me be clear. I never joined the Blizzard Group. I've got stuff to take care of. We'll talk later.]

He sent the message, powered down his screen, and slid the phone into his pocket.

Seconds later, Lily's next wave of texts started pouring in.

[Lily: Wait! What's going on here?!]

[Lily: But Lady Fubuki clearly told me that you joined. Did you back out last minute or something?]

[Lily: Don't leave me on read!]

[ʕ.•᷅ࡇ•᷄.ʔ ʕ.•᷅ࡇ•᷄.ʔ ʕ.•᷅ࡇ•᷄.ʔ][…]

No matter how many messages she sent, none were opened. Shinji's phone remained silent.

Aside from actual calls, he always kept it that way, no vibrations, no notifications. He only checked it when he had time. That's how he liked it. Total peace and quiet, no interruptions.

…

With a quick flash of chakra and a swirl of space, Shinji used the Flying Thunder God Technique to teleport straight to the Hero Association's Z-Branch.

Inside his Kamui space, he had stored the corpses of Carnage Kabuto and Beast King, both former elites of the House of Evolution. They made perfect evidence for his monster extermination report.

However, neither of the two had ever been officially cataloged by the Association. That left the staff scratching their heads on how to log the kill.

"Mr. Kamui," the examiner said, smiling awkwardly, "we don't have any existing data on these two, so we can't give you a finalized contribution score just yet."

"How about this: we'll submit your case to the higher-ups and send the monster bodies to HQ for analysis. They'll handle the classification and score afterward."

"That's fine. Handle it however you want." Shinji's tone was relaxed. He wasn't in a rush.

Honestly, he was probably the only hero who'd go out of his way to bring the corpses as proof. Saitama sure wouldn't have. He'd just punch and walk off.

As long as the Association didn't forget to give him proper credit, he was content.

…

Three days later, the results from HQ finally came in.

Carnage Kabuto had been given a preliminary classification as a Dragon-level threat. Beast King, meanwhile, was designated Demon-level. Seemed accurate enough. The Association never bothered with detailed subdivisions like mid or high-Dragon anyway.

But with the report came something else, an unexpected wave of suspicion from HQ.

After all, Shinji was still officially just a B-Class hero, yet he'd dragged in the corpses of monsters that even the average S-Class would've had serious trouble with. That alone raised more than a few eyebrows.

Naturally, a high-level executive meeting was called almost immediately. All the attendees were upper-echelon officials of the Hero Association.

"You've all heard about B-Class Rank 4 hero 'Kamui', right? So, what does everyone think?"

"My take? We wait and observe. If he keeps taking down Demon-level and even Dragon-level threats like KING did, then we don't have anything to worry about."

"Agreed. If he's another silent powerhouse like KING, there's no reason to doubt him yet."

"..."

In the end, the majority sided with caution, and the leadership decided to keep an eye on Shinji rather than take any direct action. They didn't try to block his rise either.

The whole meeting lasted under ten minutes.

If it had been about Saitama or Genos, and if those two actually did more public hero work, this same group would've easily spent two more hours debating their hero names and titles. But Shinji? Fast, quiet resolution.

One of the few genuinely competent officials, Sekingar, sat there feeling thoroughly unimpressed. It wasn't that he didn't trust Shinji, it was just annoying. A supposedly high-stakes meeting, and nobody had taken it seriously. No deeper questions, no planning, nothing. Just brushed aside like a routine formality.

It was ridiculous.

…

Afterward, thanks to the magnitude of his contributions, which far exceeded the expectations of any B-Class hero, Shinji was promoted directly to A-Class.

Because this was a leap in class rather than a simple climb within B-Class, he didn't displace Fubuki from her Rank 1 spot, nor was he required to take any sort of promotion exam.

His first bump came from taking down the Demon-level Beast King, which earned him A-Class Rank 39, the very bottom of the ladder. But when the Association reviewed his defeat of the Dragon-level Carnage Kabuto, they couldn't ignore the weight of it. He jumped straight to Rank 5.

So why didn't he go even higher?

Simple: Rank 1, Sweet Mask, was a major PR figure for the Association. His looks, charisma, and public appeal were too valuable to mess with. Meanwhile, Ranks 2 through 4 were occupied by disciples of Atomic Samurai, a man the Association had to tread carefully around.

So, while Shinji deserved more, Rank 5 was the ceiling they were willing to offer... for now.

The official explanation? His combat history wasn't deep enough.

But everyone with a brain knew the truth: hidden politics, favoritism, and carefully guarded hierarchies still ruled the hero world, no matter how flashy or noble it looked from the outside.

[Alert! Host has been promoted to A-Class Hero. Reward unlocked: 30 points + Mangekyō Sharingan (Shisui)!]