Disclaimer: Hey everyone, this is KiloWhiskeyOscar bringing you my very FIRST crossover story… EVER. Like Seriously, FIRST EVER crossover! I've never done anything like this on this scale and with so many superheroes from different universes.

Special thanks goes to Mato Filipovic for the cover art.

I offer a quick apology to anyone whose favorite hero wasn't included, and I don't own the rights to Marvel's Avengers or DC's Justice League. Enjoy!

There exists more than one Earth. A parallel world so similar to ours and yet so different in either the subtlest or the most drastic of ways. It can be difficult to truly comprehend the differences between this Earth or the next. Only the greatest minds with the most advance means to reach out to these other Earths could possibly understand these vast differences. How similar would another Earth be to this one, and how much more different could it possibly be from this one? What would be found there, and whom would be foolish enough to stand in my way? Whomever they may be, they will fall to my might… MY genius, for I am Victor Von Doom.

AVENGERS x JUSTICE LEAGUE
ALL STARS

Chapter I

The world was a place full of remarkable people. Each of them was vastly different from the others in a variety of ways, some too radical to ever be considered possible. Yet, they existed. Most of the time, these remarkable people stood apart from the so-called normal ones. The normal people of the world would've often considered them freaks of nature. But every so often, these remarkable people joined together to form a group of individuals who banded together for one purpose; to protect the world. If it were that they couldn't protect the world, then they would avenge it. That was what heroes did.

But Victor Von Doom didn't believe in heroes. Victor Von Doom saw them as nothing more than a hoard of nuisances. To a man of his vast intellect, heroes like the Fantastic Four or the X-Men or even that annoyingly irritating Spider-Man were acted with unlimited power and no accountability that often interfered with his own plans of protecting the world. Of course in his case, protecting the world meant conquering the world. Thanks to his most recent excursion to New York City, particularly to the Baxter Building, which was the home base of his scientific rival Reed Richards, Doom now had an alternative to his personal dilemma. For if he was to be repeatedly halted in his conquest of this world, then he would conquer another.

Still, it was of little surprise that his actions would draw the attention of a group of heroes that weren't the Fantastic Four, but were just as annoying. He monitored the invasion of his home country of Latveria by the Avengers. One monitor each showcased the individual heroes. There was Steve Rogers, better known as Captain America, considered the world's first Avenger and a holdover from World War II. He aided in the defeat of HYDRA and its leader, Red Skull, and then seemingly perished, only to awaken years later as the leader of Earth's Mightiest Heroes.

There was Tony Stark, a self-proclaimed genius, billionaire, playboy and philanthropist. Having been injured and briefly held in captivity, he developed a series of armored suit to combat the so-called forces of evil, of which Von Doom was considered a part. The world came to know Stark as the Invincible Iron Man.

Then there was Dr. Bruce Banner, a scientist in the field of gamma radiation. He was only so remarkable due to having been exposed to the very field he studied, which turned him into the Incredible Hulk. The Hulk was a manifestation of Banner whenever he was angered or stress, and he was a military target for years. It was a pity that Thunderbolt Ross had yet to catch him. As much as the Hulk was looked upon as god-like, Doom knew better.

Thor was the literal god among the Avengers. He was the Crown Prince of Asgard and the heir to the throne, who often had to fight to protect Earth from the mischievous machinations of his adopted brother Loki. Thor was the only one worthy of wielding the mighty hammer Mjornir, although Von Doom often considered himself to far more than worthy. It was a shame the world would never appreciate that fact.

There was room amongst the Avengers for normal members, such as Clint Barton and Natasha Romanoff, known as Hawkeye and Black Widow respectively. Both were top members of S.H.I.E.L.D. before joining the Avengers. Hawkeye was a master archer and the Widow was a Russian born assassin and spy. Those were quite the talents to have, if only to make up for their lack of actual superpowers. Then again, Von Doom was a genius and had no real need for such parlor tricks.

The Avengers also had room in their ranks for machines, particularly the android known as the Vision. A construct of the technological terror known as Ultron, the Vision proved in his, not its, own way to be a treacherous as its creator. He turned on Ultron to join the Avengers and had fought alongside them ever since. If there was one thing Victor Von Doom despised, it was a traitor.

Finally, there was Carol Danvers, better known to her allies and the world as Captain Marvel. Like he'd done with the other Avengers, Von Doom studied the history of the former Air Force pilot turned Human/Kree hybrid heroine. It was amazing what splicing Kree DNA with Human DNA could do to a person.

But as much as he respected the Avengers, Von Doom found the incursion into his country as a slap in the face. He still focused on his work; analyzing and modifying the device that was taken from the Baxter Building. He'd let his Doombots handle the Avengers while he worked, for the last thing on his mind was getting his hands dirty. But as his castle shook with the heavy shudders of battle, he knew it was only a matter of time before they broke into his home. And, Doctor Doom would most assuredly defend his home.

A moderately large squad of Doombots marched through the forests below Doctor Doom's castle and just outside of the town that rested below. Several smaller groups broke away from the main group, deployed long range guns and started shooting at an incoming target. Within a moment, that target ripped through the nearest group Doombots with ease. The Hulk let out a mighty roar before lunging to the next group of Doombots, tearing limbs and head clean off and then tossing said appendages to the next hapless machine.

Nearby, another group of Doombots surrounded Captain America and Black Widow. The machines proved less of a match for the two Avengers, as Captain America and Black Widow worked cohesively against them. Widow made use of her stinger gauntlets and fried the circuits of two or three of the machines. She then wrapped her legs around the head of another bot and shorted it out with her gauntlets before shooting another one with her sidearm.

At the same time, Captain America bounded in between the others. He punched and kicked every Doombot that came close to him, sometimes hard enough to punch right through their chassis. Some of them had guns and fired at the duo, but Captain America blocked the stream of bullets with his always-trusted shield. The bullets bounced from the vibranium-made shield and then Captain America tossed it. The shield sailed across the field and cleaved pieces of the Doombots off clean before returning to its owner.

Black Widow finished off another bot and briefly regrouped with the leader of the Avengers. "Well, I guess Victor knows we're here." she said.

"It doesn't surprise me. He knew this was coming when he had his Doombots infiltrate the Baxter Building," Cap replied before pressing his fingers to his helmet. "Stark, you find a way into the castle yet?"

Flying high above the castle, Iron Man replied, "Doom's improved his security measures since the last time we paid him a visit. I'm picking traces of alien technology spiced into his castle's defenses. Looks like Doom had some holdover gear from the Skrulls."

Back on the ground, Cap replied, "Good thing we've got the Vision searching for an alternate route. Keep looking for an opening, Stark. We'll hold these things off." He didn't notice a Doombot rushing toward him… nor did he have to.

Hawkeye shot an arrow into the machine's back and it exploded into fragments. "Meanwhile, I'll just be here watching your back."

"Clint, behind you." Widow shouted.

Before Hawkeye could react, a Doombot was nearly on him. It too was blown to pieces by a bolt of energy, and Captain Marvel flew into sight. "And I'll be watching yours, Barton."

"Don't get too cocky, Danvers." Hawkeye quipped.

"You smooth talker, you!" said Marvel.

"Heads up. You've got more Doombots approaching." Iron Man replied.

Captain America and Black Widow were the first to notice the oncoming horde of Doombots converging on them, and there were a few too many to take out at once. But long before the Doombots could open fire, a massive bolt of lightning that destroyed the frontline machines suddenly set them upon. Thor dropped down from the sky like a very literal god, Mjornir in hand. With a mighty swing, he threw the hammer into the group of hapless drones and sent bits of them flying every which way. The remaining Doombots attempted to retreat but Hulk cut them off before pummeling them to pieces.

More Doombots approached. Thor called back his hammer and after a brief exchange with Hulk, and a smile, he said. "How about a friendly wager, monster; the one who destroys the fewest machines must clean the Quinjet for a week."

"Get ready to lose, blondie." Hulk replied just as a Doombot rushed for him… and he smashed its head.

Thor smirked and bashed another Doombot in the torso to destroy it. More Doombots approached in packs, so Thor and Hulk rushed forward to meet them head on. Hulk pummeled and ripped apart several bots quickly while Thor bashed and electrocuted several more. They exchanged friendly glances again, neither wanting to lose the bet they made before attacking the next wave of Doombots. It proved to be a very unfair situation; the Doombots need reinforcements while Hulk and Thor pummeled, hammered, bashed and, in Hulk's case, smashed them.

Meanwhile, Iron Man and Captain Marvel flew overhead taking every available potshot at Dr. Doom's castle fortress. The fortress had its share of defenses, including tower-mounted anti air guns. They fired often and rapidly, but Iron Man and Captain Marvel were two very small targets to hit. In response to being target, they fired back. Captain Marvel fired a series of energy blasts that weren't strong enough to penetrate the armor on the guns, but because of their tracking system, the guns ultimately shot the blasts as they came. It allowed for Iron Man to move and send a missile barrage to the gun closest to him. That gun was hit hard and eventually destroyed. The next gun struck Iron Man and sent him spiraling out of the Sky briefly, but it bought Captain Marvel the time she needed to focus her energy into a concentrated blast that destroyed the next gun. By that time, Iron Man was airborne again.

"Jocasta, what's the status on the Vision?" Iron Man asked.

Jocasta was the artificial intelligence of the Avengers and the replacement for J.A.R.V.I.S. following the latter's destruction at the technological hands of Ultron. She replied to Iron Man, "The Vision is closing in on the primary concentration of power within the fortress. He should be able to disable the energy field from the inside."

"Thanks Jo. You get that, Cap?" Iron Man asked.

Back on the ground, Captain America destroyed another Doombot while Hawkeye and Black Widow double-teamed another. He replied to Iron Man, "Affirmative. We'll keep these things occupied until Vision gets that field down. When that happens, you and Danvers move in and we'll regroup and follow."

Hawkeye and Widow had been listening and Widow said to Cap, "Vision's cutting it pretty close, Steve."

"Yeah, I was just starting to get to know these bots." Hawkeye added just before he fired a trifecta of arrows that exploded and destroyed three more Doombots.

"Let's just keep fighting, people, and let Vision do what he has to do." Cap replied and ducked the flying torso of a Doombot.

When he rose back up, he caught sight of Hulk and Thor continuing to beat down the Doombots as they kept coming. Thor bashed the Doombots that came closest to him and electrified those farthest away. At the same time, Hulk did what Hulk did best, which was smashing any Doombot stupid enough to confront him. He even went so far as to bite their heads and limbs. Through all the chaotic nature of their assault, it was easy for the rest of the team to forget that Hulk and Thor were engaging in friendly competition.

"Man, I hope Hulk doesn't biting my head off." Hawkeye said to Widow.

"Please don't give him any ideas, Clint." Widow replied.

In a control within the fortress of Doctor Doom, several Doombots diligently operated the control for the fortress defenses that kept the Avengers at bay. But the Doombots had no real perception of their surroundings, so they had no idea that the Vision was appearing from underneath the floor of the control room. It had been thanks to his density-manipulation powers that he'd spend much of the mission phasing up from the hills below the fortress completely undetected. Before the first Doombot to see him could react, Vision had already blasted it with a beam blast from his forehead.

The other Doombots reacted to the intrusion by shooting at Vision, who again manipulated his density to become rock-hard. Then he phased back down into the floor, appearing behind one of the Doombots and silently alerting the others. They opened fire once again and Vision phased back down, while the one Doombot was ripped apart by the shooting of its fellow machines. Vision reappeared again and took flight above the Doombots, using his beam blast to rip right through them in once quick, swift motion. The beam cut each Doombot in half, lopped off limbs and left them in heaps of metal and circuits.

Vision levitated to the floor and approached the console, studying the control for the proper system to deactivate the field. "Vision to Captain America, I have successfully infiltrated Von Doom's stronghold. I am preparing to lower the field."

"Do it, Vision. Iron Man and Captain Marvel will meet you inside." Captain America replied.

"Commencing shut down of the field. Stand by…"

Vision worked the controls at a speed that was sudden and faster that the hands of any human. Being an android certainly presented Vision with certain advantages that most humans didn't have, except maybe Tony Stark… and Ultron. Vision was created by Ultron to kill the Avengers, but Vision chose instead to join them. He'd proven a valuable member in the past and he was proving it again. He worked the console until he looked outside of the big windows. A ribbon of bluish green energy zipped down the height of the window, and Vision caught a glimpse of Iron Man swooping passed.

"Field's down, people. Jo, give me a location on Von Doom." Iron Man said.

"I'm picking a sizable power surge near the center of the fortress. Doctor Doom clearly has an experiment going on with the device he'd stolen from the Baxter Building." Jocasta replied.

"Good Job, Jo. Cap I've got a location the big guy. I'm going in to say hello." Iron Man said and rocketed forward without waiting for a response from Rogers.

Captain Marvel did respond, "I'm on your right, Tony. Let's get that metal-headed dick."

"You do realize that just came out wrong, right Danvers?" Iron Man asked as he and Captain Marvel made their move.

"Did it?" Carol quipped.

On the ground, Captain America said, "We've got a clear shot. Hulk and Thor, clear a path for us."

Sure enough, Thor and Hulk took the frontline and started plowing their way through the last few Doombots. Captain America, Black Widow and Hawkeye followed the path, taking out any stragglers that were still functional. The front door was closed, but that didn't stop Hulk from throwing himself into it. The door was shattered but not broken through, so Thor called down lightning using Mjornir and focused it on the door. The door was weakened further, just enough for Hulk to smash through completely. The way was open and Captain America led the Avengers into the fortress knowing that Doctor Doom was waiting.

In a massive chamber replete with a series of technological apparatuses and massive screens of the battle outside, Doctor Doom stood before a machine that was operating. In the center of the machine was a sort of electromagnetic field, and within that was a small rectangular-shaped object swirling in place. Two Doombots, theses ones more heavily armed than the others, stood at the door that within moment burst open. Iron Man flew into the chamber and made immediate work of the two Doombots. A couple other Doombots attempted to defend the chamber, but Iron Man used perfectly timed repulsor rays to frag them into pieces. Through all the quick chaos that occurred, Doctor Doom never turned once and Iron Man dropped to the floor to approach the villain directly.

"Science fair's over, Victor. Hand over the device and maybe I won't trash this place… at least not without downloading your files first."

Even without turning to face the Avenger directly, Doctor Doom was aware but unafraid to reply with cold conviction, "For all your intelligence and ingenuity, Stark, you still lack the intellect to truly comprehend the reasons for which I now possess this device."

"Ya-huh. You had you mindless metal minions steal that device from Reed Richards. I don't see how that's hard to understand." Iron Man replied just as a ping came into his helmet.

"Tony, I'm picking up a considerable amount of energy coming from the device, typically indicating what I can only surmise involves interdimensional properties." Jocasta stated.

"Monitor the power readings and keep me posted, Jo," Iron Man said before returning his focus to Doctor Doom. "You planning a vacation, Victor?"

For the first time, Doctor Doom turned to address Iron Man directly. "You can't possibly fathom the scope of what I've acquire, no more than what that feeble-minded Mister Fantastic could."

"It's an interdimensional portal device. Wasn't really that hard to figure out." Iron Man claimed.

"I see you've had you're A.I. scan the device, but it's so much more than that. This device is not of the makings of Kang or the Kree or the Skrulls or Apocalypse or even of Thanos himself. For it is not even of our own universe. Not even Reed Richards could fathom its origins."

"And you can?" Iron Man asked just as Captain America and the rest of the Avengers arrived in the chamber.

"We miss anything, Stark?" Hawkeye asked.

"Not much!"

"We're giving you one chance to surrender, Doom. Hand over the device and we'll leave peacefully without further incident." Captain America declared.

"You trespass upon my homeland of Latveria, invade my castle fortress and expect to leave so easily?" Doctor Doom asked coldly.

"You have my word, Doom. As long you allow us to leave with the device, we'll depart Latveria without a fight." Captain America stated.

"You will depart from Latveria now, or suffer the consequences of your actions." Doctor Doom declared.

"I don't think he's going to listen, Cap." Hawkeye said.

But Cap wasn't about to give up. "We're not leaving until you hand over the device, Doom. End of story."

"Very well, Captain. You've made your choice," Doctor Doom said and pressed a switch on his right gauntlet. Within moments, a whole platoon of Doombots stormed into the chamber and surrounded the Avengers. "Now, you will all suffer for it."

Author's Note: That's the opening chapter done with the first look at the Avengers line-up. Don't worry; will see the Justice League pop up at some point.

For the record, Loki was originally intended to be one of the main antagonists. I went with Doctor Doom instead because he deserved better from the atrociousness of his portrayal in the anything-but-Fantastic Four movies. The other main antagonist will be Darkseid. Sorry if you were expecting Lex Luthor.

First Chapter, so first reviews get a shout out for on the next chapter.