Disclaimer: I do not own Marvel Cinematic Universe, Arrowverse or anything else you may recognize

I will continue this story after exams but I decided I needed to at least get this up.

I would like to thank Arrowverse Fan 217 for giving me this idea and a lot of input for it to help me with it. I'm very excited to write this story.

For the timeline, Arrow Season 5 and Flash Season 3 have happened but differently.

In Arrow, the main difference is that Oliver stopped Adrian from killing himself in the end and so Lian Yu didn't blow up. Adrian, Talia, Harkness and Evelyn are imprisoned in Lian Yu with no hope of escape while Samantha is alive and shares custody of William with Oliver. Earth-2 Laurel had turned over a new leaf and stays with Quentin and is trying to help Team Arrow. Felicity did work with Helix in the beginning but the others found out and after calling her out on it, convinced her to leave them for good.

In Flash, Barry didn't create Flashpoint at the end of Season 2 but Caitlin's powers still manifested due to the Particle Accelerator explosion in Season 1. And Savitar did happen but he was actually Future Flash from the 2020 timeline which Thawne erased. Saves us all a lot of headache.

The Dominator Invasion also happened but the Dominators did that simply because of the meta-humans, not because of Flashpoint.

As for Arrow Season 6, only the Deathstroke episodes have happened so far and nothing in Flash Season 4 has happened because that season is the worst. And Barry got together with Caitlin instead of Iris because WestAllen is a horrible pairing.

The first two seasons of Legends of Tomorrow happened the same but in Season 3, while Rip Hunter created the Time Bureau, he did not make the Legends retire temporarily and they all worked together to fix the Anachronisms. Ava Sharpe is not a clone but a real person and is not in a relationship with Sara. And because of the cooperation between the Legends and the Time Bureau, the mess with Mallus got solved a lot sooner with Constantine's help who has also joined the Legends but Wally hasn't. And Nora Dahrk has also joined the Legends.

The first two Seasons of Supergirl have also happened but not the third one. I really don't care about that show and Legends of Tomorrow much to be honest so I don't care about their timelines (or lack thereof in LOT's case) either.

And this kind of story has been done before by both Stand with Ward and Queen and Raptor2216 so I will try to do this differently but some comparisons with those stories are inevitable. Still, this is going to be my own thing and very different from their stories- "Torn between two earths" by Stand with Ward and Queen and "Worlds Collide, Heroes Clash" by Raptor2216. If you haven't checked those out, you have to because they are amazing.

Once again, thank you to Arrowverse Fan 217 for all of his help. With that out of the way, let this begin.

Chapter 1- Battle against machines

Star City

Oliver Queen, Laurel Lance of Earth-2, John Diggle, Rene Ramirez, Dinah Drake and Curtis Holt returned from their nightly patrol as Felicity Smoak was on the computers.

"How was the night?" She asked them.

"Not much of an issue to be honest." Oliver told her.

"Nothing more than a mugger or two." John said.

"I need to get home quickly." Rene said as he put his guns and mask away.

That was when Oliver got a call. It was Thea Queen, his sister.

He picked it up, "Thea?!"

"Ollie!" She said, "City Hall has just been attacked!"

"What?" He asked in shock as he put the phone on speaker and everyone else listened.

"By who?" He asked.

"Robots!" A horrified Thea said, shocking everyone else too, "They just-They just came out of nowhere. The guards are outgunned!"

Felicity pulled up footage and looked at tall yellow robots flying around the building, firing at it and killing some guards around.

"We're coming Thea!" Oliver said as he cut the call.

"This night got so much worse!" Laurel said.

"Come on!" Oliver told them.

Later

Two of the guards were gunned down by a flying robot when a sonic scream sent it flying off and crashing into the ground.

It was Black Siren. Two of them tried to fire at her but she flipped around to dodge and with another sonic scream, destroyed them too.

One of them was hit by an arrow in the neck which exploded, destroying the robot as well.

The Green Arrow lowered his bow as Spartan and Wild Dog fired at some of the robots, getting one each before taking cover behind a trash can to avoid gunfire.

The Canary fired her own Canary Cry and destroyed one more robot as Mister Terrific threw his T-Spheres and they unleashed a small sonic wave, destroying another robot.

Green Arrow fired at another and it died down. But more kept coming. Team Arrow and the SCPD were all getting overwhelmed minute by minute.

"Overwatch!" Green Arrow said as he flipped behind a car to avoid a shot, "They're too many. We need backup. Call Team Flash, the Legends and Supergirl as well."

"All right." Overwatch said from the other end, "Contacting them."

Oliver flipped around to avoid a few more shots from the robots as Black Siren and Black Canary destroyed the offenders with their Canary Cries.

Green Arrow fired another arrow and it multiplied into 3, hitting 3 robots and taking them down. Mister Terrific was about to throw his T-Spheres again when a robot blasted the ground behind him and he was sent flying off and knocked out.

Spartan got the offender with a shot as Green Arrow took down another robot and ran into City Hall. One of the robots tried to blast him but he avoided with a flip and smacked it with his bow before sticking an arrow in it and flipping away as the robot exploded.

He ducked to avoid another robot's shot from behind him and turning around, fired at it with an arrow and it exploded, destroying the robot.

Green Arrow walked further inside as a robot appeared in front of him and was about to fire when someone hit him from behind with a chair. It turned around to see Quentin Lance.

It aimed at him but Green Arrow fired at it and it died down. Quentin sighed in relief, "Thank God you are here."

"Don't thank anyone yet." Green Arrow said, "They're too many."

Thea arrived at that moment and the two siblings hugged each other.

"You okay, Speedy?" He asked her.

"I am." She said, "They just popped out of nowhere all of a sudden. I have no idea how!"

"No worries." Green Arrow said, "We will stop them."

"Green Arrow." Black Siren said via earpiece, "Team Flash and Supergirl have arrived."

"I'm coming." Green Arrow said as he nodded at Thea and Quentin and running to the window, flipped out before firing a grapple arrow at the opposite building and using it to swing down just as a speeding blur destroyed a robot and Flash stopped next to him.

"So, robots now?" Oliver asked Barry.

"They're a step down from aliens though." Barry said.

"Yeah, but John won't like it." Oliver said and the two chuckled as Barry sped around and generating 3 lightning bolts, threw them at 3 robots, destroying them all as Vibe fired his vibrational blasts at one, destroying it while Killer Frost froze one till it stopped functioning and crashed to the ground.

A robot fired at Vibe but he opened a breach and then opened another one in front of the robot, redirecting the blast at it and destroying it.

Kid Flash also sped around, destroying a few robots as Flash hit one with a supersonic punch and Supergirl hit another one with her heat vision, destroying it as he she landed on the ground.

Two of them fired at her but she was unaffected as she used her freeze breath to freeze them both and flying at full speed, rammed into some more, destroying them all.

J'onn was there too in his Martian form. He phased through a robot and becoming tangible again, grabbed it and destroyed it.

And then the Waverider appeared in the sky and fired a gun at some of the robots, destroying them as it landed and out stepped the Legends.

Oliver, Barry and Kara smiled on seeing their backup as Mick fired his Heat Gun, burning some of the robots while Firestorm also destroyed some of them.

Zari flew into the air and destroyed two of the robots with an air blast and using her vortex, defended herself before destroying two more with her wind blasts.

Nora Darhk telekinetically ripped one robot apart.

Nate steeled up to defend himself from the blasts and grabbing a robot, threw it down and punched it hard, destroying it while a robot was about to fire at him from behind but died down as Ray Palmer flew out of it and growing back to normal size, destroyed a robot with an energy blast.

Sara flipped around to avoid some blasts before throwing 3 shurikens at the robot's neck, putting it down while Oliver fired at another robot, taking it down as he walked up next to her.

"Just like old times." She smirked.

"Yeah." He said as they fought back to back.

One of the robots fired a blast at John Constantine but he stopped it telekinetically and moving out of the way said, "You're not roasting me today, mate."

He then took out a lighter and putting the flame on, chanted in Latin, "Lyft sy þe in bǽlwylm ac forhienan se wiðere."

With that, the flame grew into a small fire and he blew on it. It hit a few robots, destroying them as he put the lighter back inside.

Oliver put another robot down with his arrow while Barry sped and punched another while Kara hit another with her heat vision, destroying it too.

That was when a giant yellow robot, almost 8 feet tall appeared in front of them. It had green eyes, with yellow pupils and several compartments on its body along with long tentacles in the places of arms.

One of its compartments opened and just as Cisco fired a vibrational blast, a small sphere flew out of its compartment. The sphere collided with the beam and it exploded, sending out a small shockwave and opening a vortex in front of them.

"Everybody get back!" Oliver yelled as Wally started speeding some of them off. Barry was about to speed one of them away when his feet left the ground and he was sucked into the vortex.

Kara flew towards the vortex to save Barry but she was sucked in too.

"Kara!" J'onn yelled and flew after her but he was also sucked in.

"Everyone get out of here!" Oliver yelled before he also started getting sucked away. Sara grabbed his arm and held onto a pole to save them both but both of them were also sucked in, followed swiftly by Cisco and Constantine.

That was when the vortex closed and everybody stared at the spot where it had been in horror.

"Where did they go?" Dig yelled, "Where did they go?!"

"Where's the robot?" Killer Frost asked as they realized the giant robot was gone too.

"Where did they come from?" Ray wondered.

"We need to find out where the robot came from." Black Siren said.

Kara awoke with a groan and looked around at all of her unconscious friends.

"J'onn." She said as she walked up to him and tried to shake him, "J'onn!"

That was when her super hearing picked up the sound of something soaring in the air and she looked in the sky as someone flew down and landed in front of her.

It looked like some kind of suit of armor. Its head, arms, wrists and feet were painted red with the face and shoulders painted yellow and the rest of it was silver. It had a chest piece in the middle.

Kara used her X-Ray vision to see a middle-aged man inside it with a small moustache and beard. This suit looked a lot like the one Ray Palmer wore.

"Stand down, thong girl." The man said and Kara looked offended.

"Thong girl?" She asked.

"You can do better than that outfit." The man said as he pointed at her skimpy suit and he did have a point, as it made her look seductive instead of dangerous, though she didn't approve of him calling her 'thong girl.'

"I need you all to come with me." The man said.

"What?" Kara asked, "Where?"

"Clearly, you're all unregistered enhanced who found their way here." The man said, "I saw you all falling out of some kind of portal."

"Unregistered enhanced?" Kara asked in confusion.

"You have not signed the Sokovia Accords." The man told her.

"What are those?" She asked.

"You don't know about them?" The man asked, "Or me?"

"Should I?" Kara asked.

"You don't know me?" The man asked, offended, "Tony Stark. Genius, billionaire, playboy, philanthropist."

Kara shook her head and Tony Stark sighed in disappointment.

"Well, you need to come with me." Tony said, "All of you."

"And what if I don't want to?" Kara asked, realizing she was on another Earth which might just be hostile.

"I will make you." Tony said as he aimed his palms at her.

"You can try." Kara smirked as her eyes glowed and the two fired.

And that ends Chapter 1. You can already spot one clear difference between this story and the other ones like this.

In the other ones, anyone who falls into the MCU falls during Age of Ultron or any time before Civil War but in this story, Civil War has already happened.

So in case there is any confusion, the Arrowverse heroes who are in the MCU are- Oliver Queen, Barry Allen, Kara Danvers, Sara Lance, John Constantine, Cisco Ramon and J'onn J'onzz.

The big robot who fought the heroes was Computo.

Next update will happen on 7th or 8th August but like I said, this needed to at least be up.

Hope everyone enjoyed and see you all next time on 7th or 8th August with another chapter of this story.