House of Evolution.
Inside the lab, Saitama curiously stared at a vial filled with crimson liquid.
"A-type gene serum. Compared to the T-type, this one adds the Extremis virus factor. If you can accept a shortened lifespan and the inability to reproduce, it's quite a decent option."
Bruce Banner smiled.
Beside him, Dr. Genus nodded eagerly, panda eyes showing exhaustion, but his gaze burning with passion.
After nearly a month of research, with Saturday's help, the House of Evolution had successfully replicated Extremis—and even improved it.
The T-type serum worked gradually, improving the body over time, results varying based on potential.
But the A-type was far more brutal. Faster results, more stable improvement—but with its own defects.
"Oh? Sounds like it won't sell well then."
Saitama scratched his head.
"Not necessarily. You're underestimating how desperate some people are for power. I guarantee people will go crazy for this. The real problem is production."
Dr. Genus explained.
Even with the whole facility running at full power, monthly production of T-type and A-type serums was only in single digits. Still, after a year, the stockpile would be considerable.
For now, they had no plans to sell. A blade could save—or slaughter. Without Saitama's permission and a solid plan, they would not release them to the public.
"Oh, so it can make people stronger? I should call that guy."
After a moment's thought, Saitama picked up his phone.
Later, at a bar.
The lively noise had died.
Panic and fear filled the silence.
Half-drunk patrons sat frozen, staring at the blood pooling across the floor—and at the broken bodies of two heroes.
Spring Mustache. Golden Ball.
One a swordsman, the other showing off his "barrage of golden balls"—both crushed by Garou.
"Too weak. S-Class really doesn't mean much these days. I'll need to find better opponents."
Garou sneered, stepping over them as he walked out. No one dared stop him.
His name spread quickly across the streets.
The Hero Hunter.
Back at the House of Evolution.
"So this is the A-type evolution serum? Price… fifty million yen?"
King, the so-called Strongest Man, stared at the vial in his hands.
Saitama had told him about a way to get strong quickly, so he came running.
But something this advanced? Even the Association hadn't heard of it.
His skeptical eyes scanned the room.
"Tank-Topless."
Bruce Banner clapped.
Mumen Rider stepped forward. Once just a C-class hero, now he too was a part of the House of Evolution, mainly as security. His strength had grown considerably.
"Beast King."
Dr. Genus gestured.
A hulking Beast King strode in, nearly three meters tall, muscles rippling. His aura made King's "Engine" (heartbeat of fear) roar to life again. At least Demon-level!
"And Mumen Rider used the A-type already. Not as effective as the T-type, but enough to show you."
Banner smiled.
Beast King grinned, baring sharp teeth. "Sorry, but boss says I gotta test you."
"Don't underestimate me."
Mumen Rider smiled grimly, fists clenched.
For months, he had not only guarded the facility but also trained using data Saturday compiled—techniques from dozens of martial schools, refined by a super-AI.
"Alright then, here I come!"
Beast King's roar shook the alloy floor as it cracked under his step. His power was terrifying—even more than the G4 Mecha King from before.
King's jaw nearly dropped. Was this the kind of monster Saitama kept around as a friend?!
But what shocked him most came next.
Boom!
Mumen Rider slammed both fists into the ground, absorbing the force of Beast King's strike, holding firm.
Then came a flurry of brutal, no-holds-barred blows.
The C-class hero fought like a madman. Even sparring, he looked ready to die—yet with technique, shifting his weight, redirecting lethal strikes.
It was raw, bloody, desperate combat.
Even many S-class heroes wouldn't dare clash head-on with a Demon-level monster like this.
And yet Mumen Rider stood his ground.
King's eyes widened.
Could it be…?
This "weak" C-class was actually a hidden S-class hero—maybe even top twenty?!
Minutes dragged into half an hour. Finally, with smoke rising from his battered body, Beast King collapsed, unable to go on.
Mumen Rider, covered in blood, stood tall for just a moment—then collapsed too.
But not before smiling. "I won!"
"Unbelievable!"
"Big Brother Mumen!!"
"Strongest Rider!!"
The C-class guards cheered wildly.
Banner calmly explained, "The A-type serum is about 30% stronger than the T-type, but comes with side effects—like shortened lifespan."
"I'll take it! I want the A-type!!"
King shouted, face red with excitement. "I don't care about lifespan! Who needs a girlfriend when I can play games instead?!"
(End of Chapter)
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