It was a normal evening and Saitama was spending it in his normal apartment washing the dishes. Monsters appeared as usual, but for Saitama, a monster showing up was no different than an insect that needed to be swatted (mosquitos were another matter).

That is, until his cyborg disciple disrupted his normality.

"Sensei!"

"Oh, Genos."

"Would you like to participate in a tournament?"

"There's a tournament that I'm already thinking of participating in though."

"I see. Do you mind if I see the tournament dates?"

"You seem awfully eager about this." Saitama noted, handing his disciple the ticket. Genos glanced over the dates on the ticket.

But the tournament was anything but fun for Genos. Not because of the participants or the location, but because of the circumstances that lead the blonde cyborg to ask Saitama-sensei for this favor.

It began with Metal Knight contacting him through a private channel.

"As a result of my experiments with interdimensional portals, I have encountered a country in another world called Fiore. In forty-eight hours, it will host a tournament called the Grand Magic Games in its capital city Crocus. I have already entered our 'guild', by which I mean a select group of heroes under a temporary name specifically for the purpose of this competition, into the tournament; we will participate for the sake of facilitating diplomatic relations."

Genos was not amused. "You were never one to mince words, Metal Knight. 'Diplomatic relations' is only an excuse to compete in a tournament and secure weapons. I refuse."

"Don't be hasty, Demon Cyborg. This mission was explicitly ordered by Executive Shicchi to help us fight the Human Monster Garou and counter the late Shibabawa's prophecy. Our world alone may not be enough for the disaster to come. Your interest of justice coincides with this mission perfectly."

"Tch."

"The tournament requires a total of five people - six with one backup. You are not the only S-class I have requested for this mission."

"Then I accept under one condition."

"What will it be?"

"That another hero of my choice enters our team."

"Is he an S-class?"

"B-class, but that will be of no consequence."

A pause, then Metal Knight spoke. "Very well. I cannot imagine why you would invite a B-class but that is none of my business. And another thing..."

"Genos, you're thinking too hard. Steam is coming out of your ears. Is something wrong?"

Genos snapped out of his thoughts. "Oh, sorry, Saitama-sensei. I just wanted to tell you that the tournament's dates do not conflict."

"Okay then. What's in it for me?"

"A cash prize of 30,000,000 Jewels and recognition as the strongest guild in the country."

"Jewels?"

"Their money system."

"So how much Yen is that?"

"This is a separate world and we don't have much communication with it so there isn't a defined conversion rate. When we get there, we can find out how much 30,000,000 Jewels will buy us."

"Okay then."

Meanwhile, in Metal Knight's hidden base, Child Emperor decided to discuss the participating heroes with his former mentor.

"Why not Superalloy Darkshine or Pri-Pri Prisoner?"

"Darkshine is already on a mission. And there are far too many pretty boys in Crocus for Pri-Pri to exercise anything remotely close to restraint."

Child Emperor nodded. By Pri-Pri's own admission, exposing him to pretty boys was like exposing a hungry wolf to a flock of sheep. His lack of restraint would flush any deal with Fiore down the toilet, and no amount of drones would be enough to keep him in check. Not that it was worth it, wasting drones to hold back other heroes.

Being Metal Knight's former assistant and the only one who can operate the communicator with Metal Knight between worlds, Child Emperor was a must-have. Ironically, Metal Knight himself was unable to go. Participants had to participate in-person, and while summoning robots was legitimate, there was no way that Metal Knight would put himself in that kind of risk.

Of the top three S-class heroes, Blast only ever appeared when he chose to, the esper brat Tatsumaki flatly refused to use her psychic powers for "a magic show", and Silver Fang was actively hunting for Garou. Atomic Samurai also refused but volunteered his disciples so they could train for when they encounter Garou. Watchdog Man refused in order to continue guarding Q-City and Zombieman and Drive Knight did not respond. King was specifically requested for this mission by Shicchi for the most secure outcome.

"But don't you think the name 'King' would cause some controversy in a monarchy, Metal Knight?"

"Fiore is ruled by a king, but only by the king of Fiore. We come from a different country in a different world ruled by people he does not know of. So unless the king of Fiore is a tyrant and a dictator we have nothing to worry about." And even if he was, no force he could muster would be enough to prevent five S-class and one B-class from escaping.

This left Pig God, Lightspeed Flash, and Metal Bat. A Disaster Level: Demon Hungry Hot Dog drew Pig God away to fight it and Lightspeed Flash and Metal Bat decided to participate, forming their team of five.

The day of their arrival introduced some last-minute changes. Metal Bat, Child Emperor, Genos, Saitama, and King all arrived, but Lightspeed Flash was nowhere to be seen.

"I just got a message from Metal Knight." Child Emperor said. "It turns out that Lightspeed Flash and Garou fought while the portal was on and both disappeared through the portal." More like Metal Knight intentionally allowed for this to happen to get Silver Fang on the team, he thought privately. Even without any objective proof, the setup was obvious.

King looked furious, although for the strongest hero, even "furious" was putting it too lightly. His glare looked like it could have come from a disturbed viper or bear. The frown on his face had the intensity of a tyrannical dictator. And the King Engine was not just booming, but roaring for blood, moreso the blood of Shicchi than the competitors of the Grand Magic Games. It was not the face of an ambassador on a diplomatic mission.

But Shicchi wouldn't have it otherwise. King going with the group was mandatory, whether as a fellow competitor or as backup in case the worst possible situation was realized. To realize this end, he sent agents for the Association after King, begging him to lend a hand, even if it cost them their lives doing so. Eventually the noise ended up being too much for King and he ended up leaving his apartment anyway and joining the group.

And Metal Knight's plot worked: Bang did arrive with his brother Bomb, Bang reasoning that it is likely that Garou may want to fight the other participants of the Games.

"So this is everyone, right?" Metal Bat asked annoyedly. "Alright, let's get going."

"HOLD IT!" The men all turned to look at the source of the shrill voice: the 28 year-old childlike psychic Tatsumaki.

"You're thinking of going without me?!"

"You refused us outright-"

"Shut up Child Emperor! What I meant was you should have let me handle this alone!"

Child Emperor sighed. In what world did "I refuse to use my magic powers for a magic show" translate to "you should have let me handle this alone"? "We're on a diplomatic mission and you're hardly the diplomatic type."

"Hmph! Hey! Are you leaving without me?!" The other six men had already begun to step through the portal already and Tatsumaki followed suit.

Meanwhile, a certain ninja watched as the bald head he has been chasing in recent months disappeared through the portal.

"Baldy! Pervert! Octopus! Glass dome! Boiled Egg!" If there was one thing the S-class rank 2 hero was good at besides being a powerful psychic, it was being a brat. "Why don't you turn back already and save us the trouble of having to scrape your corpse off the floor of the stadium, huh?!"

"It was part of Demon Cyborg's request, which Metal Knight agreed to." Bang explained, having deduced the events that lead up to Saitama's participation. "I have little need to say this again, but you will not find him disappointing."

"And even so, he's still backup. Might as well let him tag along." Child Emperor said nonchalantly.

The group had exited through an enormous metal gate, around which was surrounded the bodies of ten or twenty armored soldiers. Most of them had lost their armor and whatever armor was scattered around was dented in multiple places.

"Garou again?" Metal Bat asked, bat at the ready. Silver Fang had only a grim glare as he walked around.

"No sign of him. Or Lightspeed Flash."

"Don't worry. None of them are dead." Bomb said, referring to the scattered soldiers.

"Of course they aren't." Garou was never one to kill needlessly, although Bang couldn't remember the last time Garou killed at all.

"They were the escort prepared for our arrival." Child Emperor noted. "Metal Knight didn't account for the possibility that Garou would have gone through the gate. Garou's from our world, so Fiore might think he's on our side. We better send someone over to the palace to clear things up quickly, Silver Fang preferably."

Of course Metal Knight knew this would happen. Child Emperor thought. If there are strong heroes on this side, Garou would cripple them, thus making it all the more important that we work together. This was the same man who was suspiciously absent for the S-class meeting, allowed the Dark Matter Thieves to shell A-City to the ground, and returned through a drone to salvage whatever weaponry was left. And if it wasn't Metal Knight, it was Shicchi, who invited supervillains to the Association's HQ to work with the heroes against the threat to humanity, although unlike Metal Knight's plan, that completely failed to work. Metal Knight's plan is cruel, but for the sake of getting rid of this monster and making them understand our position it is necessary.

"It's a dark place for a welcome." Saitama noted dully.

"Don't worry, sensei. Child Emperor and I have plenty of light sources. We should be able to find our way out of this dungeon."

"Alright."

"Garou has also made his way out of this dungeon," Bang noted. "I doubt it will be too difficult if we find an exit ourselves."

After ten minutes of being unable to find an exit, and having concluded that they were actually quarantined because of Garou, Tatsumaki leveled a sizable chunk of rock and the group crawled to the surface.

A/N: So, this is the prologue. Fairy Tail will appear in the first (next) chapter, but until then, hope this is a good start. It's been some time since I've published anything.

I've also noticed a few mistakes that I might have missed out the first time, as well as scenes that could be improved, so I may edit some chapters as I go.