Serious Saitama

Chapter 1: 70% of the Planet


It was total pandemonium. It was chaos. This was the crisis the Hero Association had been put together to fight. This was the crisis which only the Hero Association was equipped to deal with.

It was the highest threat level: Kami.

Reports from all over were indicating that the invading force of underground monsters were strong. Too strong. Anyone but an S-Class Hero could only stall them, not fight them head on and hope to defeat them. Entire cities were being annihilated, even as the S-Class Heroes were dispatched to the cities they could protect, dooming other cities too far to be reached before they were effectively crushed by the subterranean uprising. A-Class and B-Class Heroes fought desperate delaying actions, while C-Class Heroes performed rescues and otherwise helped with evacuations.

That didn't trouble the bearded man who was directing all of the operations, however. What bothered him was the concentration of the enemy threat on Z-City, and how it was being halted. Every S-Class Hero except for Blast was accounted for, halting threats in other cities. Likewise every A and B-Class Hero was accounted for, fighting desperate stalling actions as they waited for an S-Class to come.

However... Shortly after the attack emerged, Z-City had been hit with 90% of the enemy forces, and something was stopping those forces cold. Something was drawing more and more enemy reinforcements to just one spot, and whatever it was... It was chewing through those reinforcements far faster than even Tatsumaki was handling her own foes when she reached them.

The coordinator decided to trust in whatever was halting the enemy there, directing Heroes as he worked to save as much of humanity as possible.

"Atomic Samurai. No more enemies," a voice drifted in. The man glanced desperately at the scanners, frowning.

"Please, Stinger and Lightning Max's group is struggling with some of the enemy in K-City. We'll send air support to get you there!"

"No need," the voice replied, grunting once before the transmission cut off.

More enemy signatures disappeared from the scanners.

"Got anything better?" Tatsumaki's voice demanded, and the administrator could hear the frown she no doubt wore.

"Fubuki's group is struggling with enemies in G-City," he noted, studying the map.

He didn't get a reply, but noted that Tatsumaki's transponder was moving with a speed towards G City which bordered on the ridiculous.

"These things hit hard," Silver Fang's voice complained, though it was easy to see he'd killed his foes. "Where to next?"

"L-City needs back up. Mumen Rider has lead some of the enemy away from an evacuation group, but I don't even know how he's lasted as long as he has," the coordinator responded, frowning. He tapped a few more buttons. "I'm sending you the coordinates now. Please try to get to him in time."

"On the way," Bang's voice replied, the transmission ceasing.

Slowly, steadily... The Hero Association was driving the fringes of the invasion back. It was straining the very limits of their resources, but every attack but the one on Z-City was beginning to die off, be driven back under the ground.

Which begged the question: What the hell was going on in Z-City that was more important to the enemy than any of the S-Class Heroes they'd fielded? Even Metal Knight, unconcerned with civilian casualties at this late stage, was not dealing as much damage as whatever was fighting in Z-City.

"Metal Bat reporting in. K-City's wrapped up. What do you want me to do now?" The punk's voice came over the transmission.

They needed more information.

"Metal Bat, something is fighting the majority of the enemy forces. The Hero Association has only been fighting the leftovers. Head to Z-City and find out what the hell is taking the brunt of this attack and give us a report," the coordinator responded, frowning at the order. He wasn't sure if it was fair to ask it of Metal Bat, but they needed the information. Badly.

"We've been hit this hard and we're just dealing with the extras?" Metal Bat's voice was equally frightened and intrigued. "I've got to see whatever the hell group is strong enough to fight ten times as many of these things as we've all been fighting until now!"

"Tatsumaki here," the esper's voice carried over the comms as well. "Unless you have something better for me to do, I'll head to Z-City as well. G-City's situation is handled."

The administrator noted that the rest of the S-Class heroes more or less had everything under control for now and nodded, "Meet up with Metal Bat, Tatsumaki. I'll send more as soon as I can."

Z-City would be where this war was won or lost, and he'd throw as many S-Class Heroes at Z-City as he had to spare, as soon as he had them.


Metal Bat nearly dropped the weapon which gave him his name as he stared across the battlefield which had once been Z-City, perched on an eight-floor building which gave him a good view of the battle in progress.

He'd fought nearly thirty of the subterraneans in K-City, and had he not been able to draw them into one on one fights while the A-Class Heroes drew off the rest, he would have been overwhelmed in an instant. They were damned near as strong as he was, but not quite. He held just enough of an edge to beat them head on.


Then he'd fought one of the large ones. It had been stronger, faster, and tougher than he was. He'd taken a few blows he would have preferred not to take in beating down that monster, blows which slowed him down even now, in the long run.

The strength boost he got from a beatdown worked for a few minutes, but Metal Bat wasn't immortal: Those muscle tears and bruises caught up with him faster than he would have wanted.

As far as the eye could see, the bodies of hundreds of the large types, and thousands of the smaller surface invaders littered the landscape of Z-City, so dense that the subterranean reinforcements needed to burrow through their dead to reach the surface.

What drew Metal Bat's attention, however, was the man at the center of it all. Bald and nondescript, dressed in nothing but some slightly tattered blue and white pajama bottoms... Even as the S-Class Hero watched, the man was killing every enemy who launched themselves at him with a single strike.

Three of the smaller subterraneans timed their jump to strike at once, odds the punk wouldn't have liked to face. The nobody in the pajama pants blocked all three strikes, grinned, and then swept their legs out from underneath them, gathering all three on his fist as he spun before driving them into the ground, creating an obscene wave of corpses from the point he'd struck, shaking the steam off of his fist before meeting the charge of two of the large ones.

The closer subterranean swung a punch at the unnamed hero, who spun around the haymaker to punch the large subterranean in the throat, blowing its head clean off before planting his hands on the dead creature's shoulders, launching himself over the other large subterranean's hands as the other creature crushed what remained of the dying one's torso.

One punch ruptured the creature's chest, blowing the large limbs away as every part of the large subterranean's torso was turned from solid to liquid in a single strike.

"HQ, come in," Metal Bat whispered, awed.

"Metal Bat, we hear you. What can you see?" The Hero Association administrator demanded.

"It's one guy. He's crushing them like Snek crushing new B-Class Heroes. Even the big ones. He's annihilating them," the punk grunted, frowning. How the hell was someone that strong!? "The enemy is digging through a battlefield littered with corpses just to get to this guy. Just in the last minute, he's taken out way more than I fought in K-City."

"Do you recognize him?" The administrator demanded.

"Not at all," the punk replied, watching as the unnamed hero crushed another dozen of the subterraneans with the same ridiculous ease. "He barely looks winded, and he's beating them down with just one punch. Are we sure this guy isn't Blast?"

"He's not. Whoever that is, he's not S-Class One, Blast," the administrator confirmed.

"He might not be Blast, but if he were in the Hero Association, he'd be S-Class One," Metal Bat disagreed, watching the man build a pile of bodies as he fought. Not all of the subterraneans were blasted into paste when hit, but not a single one of them stirred after taking a single hit. He glanced up to see Tatsumaki arriving on the scene, the green-haired esper's mouth forming a silent O at the destruction in front of her. Metal Bat smirked. "Did someone get upstaged, Tatsumaki-chan?"

The woman's temper must have been on thin ice, but thankfully her shock at the scene in front of her prevented her from going full tsun-tsun on him, as Metal Bat felt his personal gravity lift, but not subsequently slam him into the tower for his impudence.

"Hmph! They were just too scared to fight me!" Tatsumaki finally declared, releasing her fellow S-Class. "They came after this guy instead of having to fight me!"

Even Metal Bat recognized the lie. He knew she recognized it, as well.

Whoever this man in his pajamas was, he was fighting on a level as far above S-Class as an S-Class was above a B-Class. Opponents that he and Tatsumaki would take seriously were being treated trivially by the bald man as he struck more and more down with a single strike.

"Why do I get the impression I'd just be in the way if I went down there?" Metal Bat grumbled.

"You would," Metal Knight's voice chimed in, the heavy artillery platform he'd been favoring lately drifting to rest on the building. The faceless head of the machine didn't acknowledge the other two S-Ranks, instead focusing on the battle in front of them. "I was debating concentrating my fire on the battlefront. Right now all of these subterraneans are focused on that bald man, and I could take out plenty of them with one strike... But then they'd scatter and focus on us instead. I won't fire until he falls. We'll only get once chance at this."

"Waiting to take the credit until the end?" Silver Fang asked, joining the Heroes on the rooftop, landing lightly next to Metal Bat.

"How long could you survive down there, Silver Fang?" Metal Knight demanded in reply. Bang studied the fight, watching the endless stream of the subterraneans as they closed on the bald killing machine at the center of Z-City.

"Two minutes. Maybe three. I wouldn't be killing them at nearly the rate he is, though," the older Hero finally admitted, frowning down at the sight in front of him.

"I could just summon a storm of rubble and annihilate them all," Tatsumaki sniffed, frowning at the enemies.

"Same problem as Metal Knight," Metal Bat countered, frowning at the melee happening in front of them. "You might take out the baldy, and then we'd have to deal with all of the ones swarming him. That's not a fight I think I can win, even if part of me wants to try."

They all silently watched the man continue to fight, effortlessly blowing through the horde with raw power, never engaging his enemies, just blowing past them. Before long, Atomic Samurai had arrived on the scene, hand resting easily on the katana at his side. The Iaijutsu master took only a few seconds of watching the fight before his jaw dropped.

"Bang, you see it, right?" Atomic Samurai demanded, frowning at the fight in front of him.

"What's there to see?" Metal Bat interjected, frowning and tapping his bat idly against his free hand. "This bald bastard is beating the subterraneans down like nobody's business. What's so surprising about it? That bastard is strong."

"He's utterly unskilled," Silver Fang stated, nodding once in agreement with Atomic Samurai. At the confused glance of every other S-Class Hero present, he continued. "Atomic Samurai and I would be A-Class Heroes, if it weren't for our skill at martial arts. In a direct, strength against strength situation we couldn't hope to stand up to the likes of even Metal Bat, let alone Tatsumaki-san: We close our gap with them through pure skill, not overwhelming power."

"So this guy..." Metal Bat prompted, earning a nod from Atomic Samurai.

"He's raw power. Just enough skill to control it, but he's as green as it comes when it comes to technique," the Iaijutsu master confirmed. "If it were equal power, any S-Class Hero outside of Tatsumaki-san would probably know enough to thrash this guy with ease, but..."

"But?" Tatsumaki demanded, crossing her arms and frowning at the one-man war the baldy was winning in front of her.

"Technique doesn't matter when your foe is so strong that technique won't evade his blows," Bang finished, gazing down at the fight with undisguised interest. "That man's blows are so strong, so fast that you can't deflect or counter them. The only way to avoid death is to dodge completely: Even a glancing blow would kill you. And he moves so fast that you'd have to be more skilled than I am to avoid them completely."

The subterraneans burrowing through the ground slowed their attacks, then finally stopped, one last one dying and leaving the unknown powerhouse with no more foes to fight. A light rain began to pour from the sky, the bald man in his tattered pajama pants blowing plumes of hot steam into the suddenly cool air as he finally rested, his work finally done.

Slowly the man tilted his head up to the rain, having regained his breath, apparently relishing the cool droplets now falling down on him if the grin on his face was any indication. The S-Rank Heroes gathered noticed then, that the only wound evident on his body was a small cut above his left eyebrow.

Silver Fang had only taken a single step towards the battlefield when one of the mountains of corpses was shattered, a new subterranean emerging from the shower of corpses littering the battlefield. Unlike the rest, this subterranean was larger than even the type the Hero Association had been calling Large. Also unlike the rest, it had four arms rather than two, and in each fist it clenched a blade which seemed to be made of pure green energy, the rain showering the region hissing as it met them.

Upon seeing the latest threat, the smile on the bald man's face was like a child seeing the sunlight for the first time. It was a smile that was pure in a way Bang couldn't describe, really. It held an echo of his own joy the first time he'd been challenged, but was somehow magnified a million times.

The smile was the smile of a man who thought he'd finally found a good fight, the smile of a man who'd trained himself to the utter edge of what was possible and wanted to fight another being who'd pushed themselves to the same limit. The smile of a man who'd finally found a being who could, until their fight was ended, be treated as his equal.

Until they found out who was the stronger.

Ignoring the corpses underneath his feet, the bald man began running with reckless abandon towards the last of the subterraneans, the last of the foes which had emerged to plague the world.

Four blades of pure energy so intense Metal Bat could taste them closed on the bald man, and he just grinned, punched, and the blades shattered, the bald man in his pajamas torquing his body to deliver a follow-up punch to the chest of the subterranean which blasted the giant being back across the shattered cityscape, pushing itself up from where it was propped up by an abandoned apartment building.

The bald man was already within punching distance when the creature raised it's head to regain it's bearing.

One punch blasted the subterranean's head clean off it's shoulders, leaving the bald man to stand briefly on the creature's chest for a moment, staring at his fist.

"My apartment!" The first words the bald superhero had said in the battle, and then the man disappeared, moving too fast for Metal Bat to comprehend. A quick glance at his fellow heroes and their astonishment at what had happened confirmed that none of them had followed what he'd done.

"...The world is clearly a larger place than we think," Bang noted, frowning a bit. "How the hell did we miss someone with that much strength?"


Author's Notes:



Plot bunny. Given the nature of the story, probably ten chapters at best. Basically, Saitama's dream fight happens, 70% of humanity is destroyed, and the Hero Association has to deal.

Basically, Saitama is basically known for how strong he is, but not known identity-wise.

Dis gonna be fun.

-Gaming Ikari