The Earth had been a lot of trouble lately. And quite frankly, it still is. Monsters keep appearing from out of nowhere. S-class heroes keep them at bay, but the lower A, B, and C-class heroes are still not provided with real challenges, preventing them from rising in their hero status. Not that they care. If a C-class hero were to fight against a real monster, then they would have quite the challenge to face.

But in the world of heroes anything is possible. For a hero with incredible power that can't be outmatched by anyone, a hero who doesn't do it for the glory or the fame, has made his debut many years ago. And yet he has yet to receive recognition for any of his actions. But this hero did not strive to to become one just to get famous. It's his hobby. He does it for fun. This hero's name is: Saitama. Or the Caped Baldy as he is registered as in the Hero Association data banks.

But we all know him as: One Punch Man.

Saitama walked through the crowded streets of City-Z, the wind blowing against his bald head, his cape flapping ever so graciously. The hero had to admit, even after the attack of Lord Boros and his alien crew, he still felt bored. There was absolutely nothing to do. He had taken out all of the monsters that appeared in the city after the invasion, but he still felt empty inside. Kind of what he always felt like to be honest. Perhaps it's irony? He wanted to become the strongest hero, a hero with the ability to defeat villains with just one punch. He got his wish after his intense training schedule… but in the end, was it all worth it?

He had a disciple—one he accidently took on as a one, mind you— but still; it was nice having him around. Genos had his own reasons for wanting to become stronger. Saitama truly wondered what would happen if Genos and the cyborg that destroyed his home-town would finally face each other. He had a feeling Genos would unleash every bit of his power, to an extent that could probably turn out to be his eventual death. Sure, he could be rebuilt every time he had taken a good beating like he always had. But what if he couldn't be fixed anymore? What would become of him then?

Saitama audibly sighed as he walked past several people on his way to the local supermarket, none of them recognizing who he was. He paid them little attention. He was used to it, after all. All the S-class heroes have their own fan club, fangirls, and lots of money. What did he have? A crappy apartment which he struggles to pay rent for. But at least he has a roof over his head. So maybe life wasn't all that bad.

Memories flooded back into his mind. His struggle to become the strongest hero. The many friends he made and the many monsters he defeated along the way. It started with a few punches. But they became less and less until he finally defeated a monster with just one punch. His enthusiasm could not be described at that moment. Those three years of training finally payed off!

But now? Well… he just didn't care anymore. Enthusiasm was a concept he could not wrap his mind around anymore. Although he had felt a small feeling of excitement when Boros made his debut.

"Excuse me, sir?"

"Huh?" Saitama said, shaking out of his thoughts. He looked around, trying to find the source of the voice who just asked him something.

"Down here."

Saitama looked down, only to see a little girl stand in front of him. "Oh." he said.

"Could you tell me where I can find the supermarket?"

"Of course. I'm heading there too. It's that-.

Saitama's reply was cut off when the ground underneath him started shaking. The little girl that stood in front of him tripped, but grabbed hold of Saitama's legs, preventing herself from hitting the ground as she looked up at the B-class hero in shock. Saitama just had a blank expression on his face as he watched the ground crack underneath them. Taking two steps backwards while in the process swooping the girl up and putting her on his shoulders, he watched as the entire ground cracked wide open, revealing a giant gaping hole. Saitama walked towards the hole, placing the girl on the ground. The girl quickly ran away, thanking the hero. Saitama looked down the hole in slight curiosity.

"I wonder how far down it goes," he muttered. Considering if he should check it out for himself, or just move on, he was about to jump in. Then, out of the hole, emerged a humongous worm. The worm opened its mouth, revealing several layers of whirling sharp teeth. The worm looked down at the bald human in front of him, chuckling grimly.

"I am the monster: Death Worm," the worm announced, his voice booming through the city. "I have come to rule over this world along with my children, who are currently ascending to your planet's surface through this hole I made with my power alone!"

Death Worm. Disaster level: Demon.

Saitama looked up at the worm, scratching the back of his head. In a way he did kind of wish for this to happen… but still, why now? He was going to be late for the bargain sale at the supermarket. The last time him and Genos made it just in time. He would not let that happen again.

"Hey," Saitama said, looking up at the worm. "Can't you delay your invasion for one day? I'm gonna be late, so could you please go back into your hole and come back tomorrow?" he asked.

"You dare to make demands, you human worm!?" Death Worm asked as he sped down towards Saitama with an opened mouth. "I will swallow you whole!"

Saitama just stared at the worm with a blank expression of his face. 'He's a worm.' He thought to himself.

The giant worm launched itself at Saitama with his mouth open and bit down hard on the hero, and in the process of swallowing, took a bite out of the concrete as well, leaving a gaping hole in it. "Fool," the worm said as he swallowed, feeling the rocks go down his throat. Looking down at the humans who were currently fleeing from the scene, fear consuming the poor souls, Death Worm chuckled grimly. "For far too long you humans have roamed freely across the Earth. For years you, your children, and the rest of this disgusting race have looked down upon those who are weaker than you. I am the king of worms. Every day I hear the screams of millions of worms being eaten by birds, murdered, and stepped upon. You humans use my children for fishing. You kill us for fun, thinking that if you cut us in half we'll just grow back. Well, we don't! How about I cut you all up? Or even better, how about I step on all of you? I am Death Worm, and I shall rule over this world."

"Well, this is something else." Saitama said to himself as he stood inside the labyrinth of sticky and slimy insides of the Death Worm. "Damnit, I'll need to get my suit cleaned again." He muttered, poking the worm's insides. "I guess I'll just punch my way out." He said, balling his hand to a fist and reeling his arm backwards. The hero was about to punch the worm into millions of pieces, as per usual with his punches, until he saw a bright light emitting from the corner of his eyes.

"Oh," Saitama whispered as he turned around. "Must be the exit." He said to himself as he walked towards the light. The light became brighter and brighter until the hero had to put a hand to his face to block out the light. The hero continued walking forward, the light becoming brighter and brighter.

Saitama felt a sudden breeze lightly tickle his face, and when he let his hand sling down and opened his eyes; he saw that he was no longer standing inside the Death Worm. No, he was standing in a field of grass.

But why a field of grass?

"That's weird." Saitama muttered to himself, turning around only for him to see that the light was completely gone. "Well… guess I'll just head for that wall." the hero said to himself as he looked up at a humongous wall that stood in front of him. Walking towards it, the hero noticed a lot of destroyed buildings. The wooden frames were rotten and decaying, indicating this place had been long abandoned. Windows had been smashed, and there was a 7-meter-tall human staring down at him...

Wait, what was that last part?

Looking up, the hero rubbed his eyes to see that there was indeed a 7-meter-tall human looking down at him with the biggest grin planted on his or her face. He couldn't really make out its gender.

"Oh, hi." Saitama said, greeting the human. "Would you mind telling me where I am, and how you became so tall?"

Instead of giving the hero a verbal reply, the human bend over and grabbed hold of Saitama. Opening its mouth, the human placed Saitama's head in between its jaws and bit as hard as it could. Instead of crushing it, the human roared in agony as it felt several of its teeth break on the skull of the human it had tried to devour. Humans weren't supposed to be this strong! Deciding it was for the best to swallow the human whole, the 7-meter human widened its yaws and swallowed the human whole. The giant human turned around and looked at the wall. The human began to walk towards a certain breach that a certain taller humanoid had made just minutes before. There were more humans to devour. The human, also known as a Titan, began its walk towards the breach, only to feel a weird sensation emitting from inside its belly. It looked down at its belly and before it could even react, a gloved hand punched right through it, and a bald human emerged from its belly. Holding his belly and falling to the ground, spraying blood everywhere which began to disintegrate when it landed on the ground, the Titan fell to the ground as it looked at the human. Its eyes became lifeless, and for some reason, the shockwave from the blast had completely shattered its nape, rendering it useless and dying.

"That's not happening twice today." Saitama said as he looked at the blood on his outfit, only for it to disintegrate. "That's pretty hot, literally." he added, wiping the remaining bloodstains off of his outfit. Looking up at the wall once more, Saitama's ears picked up noise he had heard many times. A sound that is a clear sign a hero is needed. A sound that means there is trouble. The sound of screams. Screams of terror. "Well, since I'm the only one around." Saitama said, looking around just to make sure he was indeed the only hero present at the wall. "I guess I'll help. Well, it's kind of become my duty, but whatever."

Bending his knees, the Caped Baldy jumped upwards and—with little effort—landed on top of the wall. He looked around him, trying to find any form of civilization. Looking down to see what was hidden behind this humongous wall, his eyes widened slightly when he was greeted with the sight of a massive city. He stared at it for a moment, walking across the wall as he looked down to see more of these giant humans walking through said city. He could see the bodies of many dead humans down below. Nodding to himself, he casually walked off the wall and descended.

Landing inside of the city, leaving cracks everywhere in the concrete he had landed on, the hero watched as two of the giant humans made their way over to him, presumably having noticed his arrival. They stood right in front of him in a matter of seconds, hunger present in their eyes as disgusting smelling saliva dripped out of their mouths.

Saitama walked towards the two Titans and in one swift blow, punched two gaping holes through their abdomens. The two Titans fell to the ground, not getting up. Saitama sighed inwardly as he continued walking forwards.

"This is weird." the hero muttered to himself, looking at several of the buildings that stood in the city. "These buildings are old, very old."

Saitama made his way towards one of the buildings, running his gloved hand over it. He looked at his gloved hand and saw that it was covered in dust, probably from the impact of his landing. Looking up at the sky, Saitama nodded to himself once more. If he was quick and precise, he might still be able to get to the supermarket in time before bargain sales end. Walking further into the city, the hero punched many more of the giant humans during his trek. Either sending them flying sky high or just punching a hole straight through them. It didn't really matter how he did it or what kind of attack he used.

Something was off, however.

He had not come across any humans yet… well, at least the ones who were still alive. He didn't know what was happening or what these monsters were supposed to be, but they didn't seem too keen to leave survivors. The corpses he had come across were either missing a leg, or their lower abdomen. If only he had arrived a bit earlier.

Could it be that these giants were eating humans? Now that he thought of it, that one giant from before tried to eat him. So, did that mean that humanity was in even greater danger? He wondered what kind of disaster level this would be.

"Probably Demon," Saitama muttered to himself as he walked past yet another corpse. Sighing to himself, the hero turned right, walking into an alleyway. "Oh."

Saitama watched in slight curiosity as two humans, both female, were currently flying through the air. On further inspection it appeared they were using some kind of machine to make them fly. They were circling around one of those giants. This one was big, probably around 10 meters. Saitama continued to observe as one of the girls tried to slash away at the giant's neck with two fancy looking swords. Her attack was stopped by another giant who grabbed hold of her, bringing her towards its mouth. The other girl screamed out in horror as she too was grabbed by the other giant who the other girl had tried to kill.

Saitama took a step forward, only for him to increase his speed, leaving a big cloud of gust behind him as he ran towards the two giants with incredible speed. Jumping up, Saitama kept a neutral expression while he extended both of his arms sideways, punching the two giants across the face as they were sent flying into two separate buildings, losing the grip they had on the girls in the process. The two girls screamed as they descended to the ground, their gear having been crushes by the Titans. Not even noticing Saitama had already carried them to the top of the wall, they continued to scream.

"Could you two stop that?" Saitama asked, putting a finger in his ear and twirling. "You're safe, I think. Just don't get off of this wall."

The two girls stopped screaming and opened their eyes. Turning to look at each other, they let out cries of happiness as they hugged each other tightly. Saitama turned around and jumped off the wall, hovering towards the city center. The two girls stopped hugging each other and were about to thank the soldier who had saved them, only for them to notice there was no one there. Looking at each other, they shrugged. They were alive, and they were probably going to stay on the wall for the time being.

Saitama was never a man to get angry. He was always the cool and calm type. This was no exception, but it was getting slightly annoying, knowing these giants weren't about to give up. He almost let out another sigh as he punched another Titan, letting it fall to the ground with a gaping hole in its face. Saitama looked behind him, seeing two more giants walking towards him. Shaking his head, the hero ran towards the two. "Consecutive Normal Punches." Saitama said in a monotone tone as a barrage of red gloved fists punched the two giants until their bodies started turning bright red. Seconds later their bodies fully exploded into nothing but a pulp of blood, tissue, and bones.

Landing on his feet, Saitama looked at his outfit. This disintegrating crap was not helping the fact that it was already hot as hell in the city. Walking further into the city once more, Saitama wondered how many of the giants he was going to come across. Because from the looks of it, this was just another one of those operations that involved him having to fight off every monster until night-time.

Saitama was about to turn right, until he heard voices. Voices that sounded quite young. Looking off into the far distance he saw one of those giants. But this giant was different. This giant had pointy ears. It also didn't have any flesh on its cheeks, revealing its teeth, and it was carrying a giant boulder. Saitama began to run towards the giant, only for him to notice that the humans were actually trying to protect it instead of killing it. Jumping upwards and landing behind a blonde-haired boy and a black-haired girl, he spoke up as he walked towards them.

"Hey, mind telling me why we're defending that thing?" he asked.

"Didn't you hear Commander Pixis' plan?" the black-haired girl growled at him, not even bothering to turn to face him. "Eren, in his Titan form, is going to seal the breach inside the wall by putting that boulder in the breach, sealing it for good."

"Oh." Saitama said, watching as the Titan struggled to carry the boulder and walk towards the breach at the same time. "That looks pretty heavy." he commented. "You sure he can handle it?"

"Yes!" the girl growled, turning around to face him. "What are you, crazy… what the hell are you wearing?" the girl asked, staring at the human in front of her. He looked weak and fragile, and his sense of fashion was the weirdest she had ever seen. She had no idea how this guy even made it up the roof she and her friend were standing on, as he didn't appear to have any ODM gear on him. "What the hell are you doing here? And what the hell are you wearing?" the girl asked.

Saitama ignored her as he just stared at the Titan who was carrying the boulder. Only for him to see another Titan walk through the breach. He stared at it in confusion, but found out its intentions as he saw its malicious smile towards the boulder carrying Titan. "Uh, you guys." He said, pointing a gloved finger at the Titan.

"Answer the damn question!" the girl growled at him.

"Mikasa," the boy said, turning around to see what was keeping his comrade occupied during these dire times. "Why are you screaming? And who is that guy?" he asked, pointing his finger at Saitama.

"That's what I'm trying to figure out, Armin." Mikasa retorted.

"You guys..." Saitama said, wiggling an obvious finger at the Titan.

"But why bother? We're so close to victory!" Armin exclaimed.

"Because it doesn't make sense for him to be up here!" Mikasa retorted.

"You might really want to look behind-."

"What?!" Armin and Mikasa exclaimed, glaring daggers at Saitama.

"There's one of those big guys heading for your boulder carrier." Saitama replied.

Both Armin and Mikasa turned around, only you widen their eyes in shock. Mikasa was about to use her ODM gear to take out the Titan that was heading for Eren, but stopped when she felt a strong gust of wind fly past her. Rubbing her eyes, she looked up to see the strange looking human from before hovering in front of the Titan.

"Would you mind moving aside?" he asked the Titan, only for it to groan and open its mouth.

"Out of the way!" a white-haired soldier screamed as she cut the Titan's eye, making it fall sideways and giving Mikasa the opportunity to use her ODM gear to cut its nape.

The Titan fell to the ground, dead.

"Go, Eren!" Armin exclaimed as Titan Eren roared as he lifted up the boulder and slammed it into the wall, making cracks appear above and below the breach, showing how much of an immense strength he had.

Saitama looked at Titan Eren in curiosity as it fell on his rear, seemingly exhausted. He cocked his head sideways, only to see Armin flying towards him, using that strange piece of machinery Saitama had seen other humans use to maneuver around. Saitama landed behind Armin, tapping his shoulder. "You need some help with that?" he asked, noticing the boy's struggle to free his childhood friend.

Armin cut Eren out, but looked up in horror as two Titans emerged from behind Saitama. "Titans!" he exclaimed, fear dripping from his tone.

Saitama turned around to see two more of those giants standing in front of him. Jumping up, he punched the two Titans underneath their jaws, sending them flying over the wall with extreme speed. Armin could only stare in shock as he stuttered to get out any words. Any other soldier among the remaining survivors all had the same experience.

How? How in the hell was a simple human capable of such a thing?

"Judging by their expressions." came a voice from above, catching everyone's attention.

Saitama looked up, only to see a human hover towards him as he landed in front of him.

"They are as surprised and impressed as I am." The human continued.

Saitama waved at him, a neutral expression on his face. "Hi."