Nobody's POV

At Hero Association HQ (A week after the Monster Association Raid)...

"But this is..." A Hero Association employee says in shock.

"What is it?" Another member says.

"Look at the radar, it's picking up signals from 25 different aircraft in space." The member says. "I'll go get Sitch."

Sitch soon arrives at the room.

"What's going on?" He says.

"Look at the radar, 25 large spacecraft seem to be closing in on earth. Each of them seem to be locked on an individual city." The Hero Association member says.

"T-That's not possible, we should've gotten rid of all the monsters." Sitch says, panicking. "Call for an emergency evacuation to the underground safety labyrinth."

"Very well, what's the disaster level?" Another hero association member says.

"This is Dragon, without a doubt." Sitch says. "No, this could even be God." 

(y/n) comes into the room, sipping on a drink.

"I think I'm lost." (y/n) says. "Can you give me directions?"

"(y/n)! Just the man I wanted to see." Sitch says, quickly bringing (y/n) over to the radar.

Sitch explains everything to (y/n), who understands the dire situation.

"What do we do?" (y/n) says. "We only have so many heroes."

"That's what I'm trying to figure out." Sitch says. "Gather all the S class heroes for another meeting."

At the meeting room.

"Come on, another meeting?" Tatsumaki says. "If we're gonna have this many meetings, I might as well live here."

Sitch walks in with (y/n), who takes a seat at his chair.

"This is a dire situation." Sitch says. "Our radar has picked up 25 unknown spacecraft in space, and each on is locked onto a different city. In our current situation, we think that the spacecraft will launch a simultaneous assault."

"So we just each go to a city to protect it." Atomic Samurai says.

"That's the problem." Sitch replies. "There are not enough S Class heroes to protect each city, plus some of you can't fight airborne enemies."

"Well, there is a work-around." (y/n) says.

"What is that?" Sitch asks.

"We go to them." (y/n) says. "We're gonna go to space and fight the aircraft there."

Some discussion follows. Eventually Sitch agrees with the proposition.

"Very well, meet up at the Z City launch site tomorrow, we can only hope that the aliens are charging up something." Sitch says.

The next day...

"I've never been in a rocket before." Saitama says.

"I think that goes for all of us." (y/n) replies.

"Why did we have to bring the B Class along?" Tatsumaki says. "This was supposed to be a S Class mission."

"I'd ask the same on why they allowed a child to go to space." Saitama says.

"Why you-!" Tatsumaki says.

"Now boarding, please make your way to the shuttle in 5 minutes." an announcer says.

Everyone makes their way to the shuttle. And once everyone has suited up, (with the exception of Tatsumaki who could already survive the vacuum of space and Metal Knight, Genos, and Drive Knight, who all all cybernetic and don't need oxygen to function), (y/n) reads an instruction manual and starts flipping the designated switches.

"Launch in 3, 2, 1, we have lift off." The announcer says.

The rocket propels into sky, starting the journey.

"Exiting atmosphere, getting rid of high-propulsion boosters and switching to secondary boosters." (y/n) says, flipping some more switches and hitting even more buttons.

"You seem like a natural at space navigation." Tatsumaki says.

"No, I'm just button mashing." (y/n) replies, still reading the instruction manual.

"What?! But then-" Tatsumaki says.

"Look!" Bang says through his suit. "I see the aircraft."

All the S Class heroes look through the windows, they see 25 alien ships all directly above a city.

"This will be simple." Tatsumaki says. "I'll just take them all out."

"No, you mustn't." (y/n) says. "Your body is still recovering and they might call in heavy reinforcements if you do so. Our only option is to get rid of them in 1 swoop, quietly so that they don't call in backup."

"I think they just did." Saitama says, pointing forward.

"What?" (y/n) says, looking over to the direction Saitama pointed at.

To (y/n) and the other S class heroes shock, a enormous figure appeared from a portal.

"I-It's bigger than the Earth!" Genos says.

"How are we supposed to fight that?" Child Emperor says.

"Let's worry about that later!" (y/n) says. "Right now, we just gotta make sure how to fight without gravity, make sure each of you attached your cables to the ship and equip your jetpack."

(y/n) and the other heroes exit the shuttle 1 by 1. As the other heroes adjust to the new fighting grounds, Tatsumaki quickly flies over to some nearby ships, compressing them into small marble-sized chunks of metal.

Angry at Tatsumaki, the giant figure uses it's hand to punch Tatsumaki, sending her crashing to the hull of the spacecraft.

"Tats!" (y/n) says.

"I'm alright." Tatsumaki groans. "Let's figure out how to fight this thing."

"I'll just slash it into bits." Atomic Samurai says.

"No! Don't!" Tatsumaki says. "I tried using my telekinetic powers on it, but i sensed that my attacks went right through it. It must be immune to attacks!"

"Nothing can connect with it's body, yet it can still hit other things? Something's not adding up here." (y/n) says.

"Launching missiles!" Metal Knight says, launching a volley of 16 high-powered homing missiles. "Nothing can survive getting hit with these bad boys."

The figure gets struck with all 16 of the missiles, they explode and a giant mushroom-like cloud appears in the aftermath.

The figure emerges from the cloud, seemingly unfazed.

"Annoying..." The figure says. "All so annoying!"

The figure swings it's giant arm, missing the space shuttle by just a few inches.

"It's going for the spacecraft!" (y/n) says. "Try to get it to hit it's own allies. Tats if that doesn't work you already know what to do."

"Hang on, I'm gonna try something." Tatsumaki says, flying towards the figure.

Tatsumaki flies right in front of the figure's chest. The figure punches at her, but Tatsumaki flies through the figure, and the figure's own fist collides with the figure's body.

The figure groans in pain.

"It worked!" (y/n) says. "We just gotta pull off a Tom and Jerry!"

"I've gonna try." Saitama says.

"I got this." Genos says. "Stay here sensei."

Genos activates his shoulder boosters, propelling him towards the figure. It tries to swing at Genos but Genos easily outmaneuvers it. Genos circles around the figure, blasting it with incineration blasts.

The figure suddenly does something unexpected. It splits itself into hundreds upon thousands of smaller versions of itself.

"What?" Genos says surprised.

The figures go into each of the remaining alien spacecraft.

"What are they doing?" Tatsumaki says.

"I don't know, but it doesn't look good." Bang says.

The spacecraft launch the hundred of thousands of mini-figures towards Earth.

"They're targeting the cities!" (y/n) says. "Get back to the shuttle!"

The S Class Heroes return to the shuttle, and prepare for a battle across multiple cities.

A.N - So this chapter is a bit different, it doesn't follow the events of the actual anime/manga. So anyways, let's hope that (y/n) and the other heroes can get this situation under control.