Hello everyone, I hope you enjoy this story, I have always been a fan of One Punch Man and Overlord, that is why I was encouraged to write my own version of a crossover between the two of them, I hope you enjoy it, I don't really speak English and I am supporting myself with a translator, so please excuse certain errors in the writing :D

WARNING: THIS STORY MAY CONTAIN SPOILERS FOR THE PLAY ONE PUNCH MAN AND OVERLORD, READ AT YOUR OWN RISK

ONE PUNCH MAN X OVERLORD

Foreword

This story begins with Saitama, he had just arrived at the new building of the hero association, he was resting, after a busy day bringing the few things that were not destroyed in his previous and now ruined apartment, saying to himself

Well, at least I have a place to sleep, when my apartment was destroyed I thought I would have to start paying rent in some other area of the city, and well I was able to recover some of my things, that is already profit

But Saitama would be taken out of his moment of reflection by Genos, who had just entered the small apartment holding a tray, where there were two cups of tea and some cookies.

Sensei, I brought a snack, I think you could use a rest, after all you had a very busy day, the Cyborg would say, placing the tray on a small table that was in the center of the room.

Oh, Genos, thank you, Saitama would respond, who had taken a seat and yet, he could feel a couple of glances staring at him.

Hey? Oh, it's you, the bald man would add, I imagine you're hungry, you haven't eaten anything since you got here, hey Genos, could you bring some pet food?

Pet food? I understand, but what kind of food does he consume?—The Cyborg would mention while pointing to the Black Sperm—I don't think I've seen an animal of that type, however, it looks quite familiar to me.

"Damn, if he finds out, I'm probably dead," the dead sperm would say to himself, who in this dangerous situation would hide between Saitama's legs. "It would be better if I stayed here, the bald guy wouldn't let them do anything to me."

Umm, it would be better to give him dog food, after all, I heard on TV that even people can eat it—Saitama mentions, moving his new pet away a little—besides, I think we can find out later, look at him, he's all skinny.

—Oh, prioritizing helping those who need it even when it is a simple animal, running to try to alleviate its hunger, another of its master teachings—the cyborg responds, writing down the situation in his notebook.

—I think it would be better if you go at once, I don't know the place very well and I don't know where I could get it.

"Yes Sensei, I'll go right away," Genos answers, leaving the room, without even having tasted a bite of the snack that he had brought himself.

And now left alone, Saitama would turn to Black Esperm

—Hey, do you eat cookies too?

"Yes, no problems boss, in reality I can eat practically anything, and those cookies don't really look bad, however, Roberto must have a stricter diet," Black Sperm responds, pointing to Robert.

—Take one of mine, even though Genos is not here, it would be better not to cut his part

—You are very generous boss—Says Sperm while trying to take one of the cookies.

However, Robert would jump between them, drawing the attention of the two bald men present in the room, and would start barking diligently.

—Robert, what's wrong with you? "I know you can't eat these cookies, the boss is giving them to me," Sperm would say with a clear tone of annoyance on his face.

—Wait a minute, a tantrum? "Do you want a cookie too, boy?" Saitama mentions, bringing the cookie that was originally for Black Sperm towards Robert's mouth.

However, it would be of no use, since Robert would categorically reject the cookie, only to go to the window and bark even louder.

—Have you found something?—I would mention Sperm—I remember that Robert was especially appreciated by Gyoro Gyoro for his incredible senses that helped him perceive anyone who approached.

"Did you say something?" Saitama would ask, who had tried to watch whatever Robert was barking through the window so he didn't hear anything Black Sperm said.

—Oh, nothing, just, Robert is acting very strange, he is usually a calmer boy.

—This, I think I know what's bothering him, look there—Responds the bald man, pointing through the window, a sudden storm—It's a little strange, the weather forecast mentioned that it would be a dry day, however, it continues being an ordinary storm

—Oh I guess you're right boss, that makes me want to thank you again, if it weren't for you, Robert and I would be in that inclement rain.

"Don't mention it, besides, I wouldn't like to be in the rain with all those strange colored rays either," Saitama would respond, eating the cookie he had in his hand.

—Color rays? That's not just a normal storm—Sperm would mention, letting a thick bead of sweat fall from his face—Surely that's why Robert got upset even though it was just a storm.

"It would be better if we closed the window, it would be terrible if my furniture got wet, it's already ruined enough," Saitama would say, preparing to close the window.

However, he would be surprised by Robert, who would jump out of the window despite being at a high altitude, all with the intention of heading towards the sudden storm, all this with great speed.

—Hey, Bobert, what are you doing? You will catch a cold and taking you to a vet will be very expensive—Saitama says, with some concern.

—Hey, boss, it's Robert—Black Sperm says towards Saitama, however, to himself—"Umm, that's strange, a simple storm shouldn't leave Robert this upset, whatever it is we should go investigate, there could be something to consume and help me regain a lot of self quickly"

—Hey, you're babbling again.

—Oh, of course, I'm sorry boss,—Black Sperm nervous—It's just that I worry about poor Robert, he runs away terrified by those rays, if he goes out alone in this rain he'll surely get sick, don't you think we should go after him? After all he is a helpless puppy

—Well, I guess you're right, let's go quickly, just let me put on my hero suit, I don't want to get my clothes wet, my dryer was buried in rubble

And this is how in less than 2 minutes Saitama was ready to leave his new department.

—Very well, I'll go look for him, I better hurry, that storm is approaching very quickly, are you coming? —Saitama says while adjusting his belt.

—Oh sure, after all Robert is my partner and helping in his search is the least I can do—Black Sperm would say while he ate cookies carefreely, almost as if those last words had no weight.

—Okay, just let me put a note to Genos, I guess he'll be confused when he arrives and can't find us anywhere.

—Well thought out Boss, now we have to hurry up.

And this is how a few minutes later Black Sperm and Saitama were already walking at a notable distance from the association building, something that would make Black Sperm happy, since despite having Saitama taking care of him, he was in the heart of the association. of heroes was something that unnerved him

"Boss, I think Robert went in that direction," Black Sperm says while pointing south. "Luckily you're very fast Boss, we didn't have any problems getting there and by the way, thank you for carrying me, right now I'm too weak to run."

"Well, after all you suggested doing it," Saitama would say with a somewhat displeased face at having to carry Black Sperm.

However, his attempt to start a conversation would be interrupted by a purple lightning bolt, which would cause a huge bang, which would scare Black Sperm and Confuse Saitama, since as soon as it hit the ground, the portion of the ground that It was hit by lightning, it disappeared completely, with no signs of having burned the area

"Boss, please don't let that lightning touch us, I know that you are very strong and that lightning wouldn't do anything to you, but it would surely kill me," Black Sperm says, holding onto Saitama even tighter.

"Hey, calm down, I won't let one of those rays hit you, we better hurry to find it," Saitama says, referring to Robert.

—Thank you very much Boss, I think we are really very close, try to listen—Black Sperm would say, stretching his ear a little.

-You hear something? Your hearing must be very good, I hardly hear anything with that storm

—Oh of course, yes, my ears are also somewhat sensitive, although of course, not as much as Robert's—Sperm would say, trying to hide his abilities—Go here, I can hear Robert slightly, the sound has been identified little by little

—Yes, I'm starting to get wet, show me which direction he went.

—Yes boss, it's towards beech, and please be careful, more and more lightning is falling every time.

And this is how Saitama would follow Black Sperm's instructions, going even further into the eye of the storm, without realizing that where he passed, a series of lightning bolts fell almost immediately.

—Boss, he's there, look, near those rocks—Black Sperm says—take him and let's go quickly, those rays are getting stronger.

And this is how Saitama would quickly grab Robert and he would continue barking desperately, but this time looking towards the sky, which would attract the attention of Black Sperm who would look up.

—Holy crap, Boss—Look up,—Sperm says with a surprised tone—is that a person?

"A person?" says Saitama, looking towards where Black Sperm indicates. "He's huge, he reminds me of that guy who visited city D."

—Careful Boss—Sperm would exclaim —Observing that that strange figure was stretching out his hand causing a large amount of lightning to descend.

And it is at that moment that an enormous amount of rays of all kinds of colors would shoot from the sky, following the three very closely, Saitama tried to dodge all the rays, first there was a green one, then another red, then one blue and so on of all the colors, however there was something very curious, every time lightning hit they could hear whispers, words like Smash, Hameha, Air Shield and so on, it sounded.

And after a few seconds, the situation reached a critical point, where Saitama, despite his tremendous speed, could not continue to maintain Robert and Black Sperm, since being considerably weakened, moving at high speed was affecting them. increasingly.

—Boss, please be careful, my stomach is turning and Robert is also starting to get dizzy.

"Hold on a little longer, we're almost out of the storm, you can stay safe in the apartment," Saitama tells him, while stopping for a second.

However, stopping for that minimum moment was crucial, since it would give time for one of those purple rays to get too close, directly impacting Saitama, but not before having released Black Sperm and Robert by mere reflections.

Saitama, upon being hit, would immediately disappear in the middle of a strange cloud of smoke.

"Boss?" Black Sperm asks, somewhat surprised.

And meanwhile in another place very far away, Saitama would find himself sailing in a kind of tunnel at a speed close to that of light, covering his entire body and cutting it completely and after what seemed like an eternity, Saitma would end up being shocked. with the ground

"What happened?" Saitama would say, rubbing his eyes in order to clear his vision.

Noting that he was in the middle of a huge open field

—Where am I supposed to be? This doesn't seem to be city A

However, his attention would be called by some cries of what seemed to be sheep, but when he turned his head, he saw some Kaijin of monstrous appearance and considerable height, which seemed to be destroying many people.

—Kaijins?—A somewhat confused Saitama would exclaim.

End of the prologue