So, this had been nagging my mind for a while now, ever since I read Stand with Ward and Queen's 'Torn between two timelines' and 'Attack on two earths'. So, in this story, MCU, X-Men and Arrowverse Earth-1 universes are on one and the same Earth and X-Men minded their own business mostly, like with Magneto and the Liberty Island, or Stryker and the Alkali Lake.

Now, for the canon changes here for the story to work:

I'm switching Evan Peters's Peter Maximoff for MCU's Pietro with Aaron Taylor-Johnson, who survived Age of Ultron and both Maximoff twins at one point find out that they are Magneto's children but don't expect them to be one big happy family.

As for X-Men films, the events up to Days of Future Past are canon and everything in this story is happening in post-DOFP timeline and the comic book events, where Logan was with Captain America and the Invaders/the Howling Commandos, are also canon and Logan has recovered his memory by now.

As for Arrow, all five seasons have happened already but without Lian Yu exploding, since don't get me started on how stupid it was and nothing else beyond that, asides from Slade's arc, is canon. As for Earth-2 Laurel/Black Siren, she is reformed, more or less and has the same backstory as from 6x15, since if not for Felicity, Oliver could've reached her sooner. As for Dinah, well, don't get me started on how the reveal of Vigilante being Vince ruined her, but in this story, it still happened but with one crucial difference, that I used in one of my one-shots, that is that unable to talk Vince down, Dinah was forced to kill him and quit Team Arrow to heal, since that's what I did in one of my one-shots and I have my plans for Dinah here. I know Dinah is a terrible character but I think she could've been better with good writing and I have a bit of a soft spot for Juliana Harkavy.

As for The Flash, everything in here is happening post-Season 5 and the only thing canon after that is Team Flash taking Allegra in and Nash Wells showing up and Ramsey/Bloodwork arc from the first half of Season 6. Plus, don't get me started on how criminal was how Cisco lost his powers before they were restored in the Crisis and then he lost them forever, since Season 5 just ruined him, so Cisco never took the cure here.

Also, there are other stories with MCU/Arrowverse crossovers, which did their own spin on Infinity War/Endgame, alongside me, so in this story, all this is happening after the heroes defeated Thanos and they split the Infinity Stones among each other, like done in other stories. As for who sacrificed themselves to defeat Thanos, no one died, since in this story Clark did the last snap to destroy Thanos, and I'm sure that Clark or Thor could've survived using the Gauntlet.

And the main villain of this story should be obvious from the title and I'm getting inspired by some comic books, X-Men Legends II: Rise of Apocalypse video game and an old X-Men cartoon from the 90s, since don't get me started on how disappointing the film X-Men: Apocalypse was.

Imagine Apocalypse being played by Eric Bana, only a bit taller and more muscular, considering Apocalypse's appearance in comic books.

Also, if I get a complaint from some trolls or idiots like Coolrod or so about what a load of crap this is or why will I not include Smallville or other flames of such nature, to paraphrase Okeer from Mass Effect: "I will inflict upon these cowardly miscreants the greatest insult an enemy can suffer: To be ignored." Don't like, don't read, move on and stop wasting everyone's time by whining. I will not care about your yammering, all the whining and flames of guest reviewers is going to be deleted.

As with my other stories, the updates will be at least one chapter per week. I do have the general idea planned out but I need some time to plan out the details.

Scott Lang will be referred to as "Scott" or "Ant-Man", Scott Summers will be referred to as "Cyclops"

Disclaimer: I do not own Arrowverse or Marvel Cinematic Universe or X-Men or anything else you may recognize.

S.T.A.R. Labs, Central City

"They've been at it for weeks now." Jesse sighed.

"Yeah." Allegra nodded as they ate popcorn, while watching a movie with Ralph, Cisco and Caitlin in the lounge and listening to Harry and Nash bicker, their voices coming from the lab and echoing in the corridor.

"This will destabilize the structure—"

"We can use dwarf star alloy to keep it—"

"That'll take too much time—"

Suddenly, there was a deathly silence as they looked at each other.

"Either they came to an agreement…" Caitlin trailed off.

"Or something's happened." Cisco said, having a bad feeling.

"Dad?" Jesse called out.

"Nash?" Caitlin called out.

"Wellses…" Cisco said as they entered the workshop and saw… three Wellses in the room and but what shocked them was one of the Wellses wearing the Reverse-Flash suit as their blood ran cold.

"You!" Caitlin sneered.

"Hello there." Thawne smirked.

Next thing they knew, a red bolt of lightning passed by them and they were all knocked down on the ground and when they recovered, Thawne, Nash and Harry had vanished.

Jesse tried to follow Thawne but he dropped a device on the ground that exploded in blinding flash of light, knocking her down as Thawne managed to escape.

"Jesse, are you OK?" Caitlin asked, rushing to her.

"He took them…" Jesse whispered, staring in despair.

"What was that?" Allegra demanded, not understanding.

"That was Eobard Thawne. The Reverse-Flash. He's back." Cisco said, his blood running cold.

Avengers Tower, New York

"What was that?" Natasha asked as she and Steve rushed into Tony's lab and saw Vision broken in half, Hulk crashed to some lab equipment and slowly reverting into Bruce and Wanda groaning and her clothes covered in burns.

"What happened?" Steve asked.

"I don't know… someone… something… attacked us… they took Tony…" Wanda gestured to the giant hole in the window as Steve and Natasha stared in shock, wondering what happened.

X-Mansion, Westchester, New York

"Maybe we can go for a restaurant tonight…" Cyclops said, when Jean groaned, clutching her head.

"Uh…" Jean groaned.

"What is it?" Cyclops asked.

"It's the professor." Jean said.

Cyclops, Jean, Logan and Storm rushed upstairs, when they saw unconscious Xavier on the shoulder of a giant blue-skinned figure in some armor and tubes connected to it as Logan pulled out his claws.

"Let him go, bub." Logan said.

"Put him down and we won't hurt you." Cyclops said.

The figure was silent and unmoving, when Logan growled. "Alright, then, guess he's not in a mood for talk."

Logan roared, lunging at the giant figure but the figure stopped Logan midair just by raising his hand. Logan was floating before the figure did a gesture and threw Logan out through the window.

Cyclops fired his optic beams but the figure raised his hand to block it, seemingly unfazed before he fired an energy blast, sending both Cyclops and Jean to the ground. Next thing they knew, the figure faded with Xavier in some kind of shimmer before they vanished.

"What was that?" Cyclops asked as he and Jean got up to their feet.

"I don't know… but whatever he… it was… it was strong… I couldn't enter its mind… but I know its name…" Jean said.

"What is it?" Cyclops asked.

"Apocalypse…" Jean whispered and in that moment, an elderly man wearing a red helmet and armor and a cape flew in, glaring.

"Well… I see Charles also had an uninvited guest in his home. So did I." Magneto said.

It was later confirmed in the show that Harry later recovered his intellect, but don't get me started on how they did him dirty.

So, what do you guys think? Is it good? Is it bad? Should I continue?

Please review and let me know if you have been enjoying this.

With regards

Bl4ckHunter