I don't own Kingdom Hearts or the Avengers. They belong to Disney, Marvel Studios, and Square Enix.

WARNING! THIS STORY WILL CONTAIN SPOILERS FOR AVENGERS: INFINITY WAR, AVENGERS: ENDGAME, AND KINGDOM HEARTS 3. IF YOU HAVEN'T WATCHED/PLAYED ANY OF THESE. DO NOT READ BEYUNLESS YOU WANT TO BE SPOILED!

YOU HAVE BEEN WARNED!

Okay, for those of you we read some of my current stories I did say I had plans to write a special crossover between the MCU and Kingdom Hearts series. Is Og Ild has graciously agreed to help me come up with this story. I would check out some of that authors story when you get a chance. They are very good. If you're a fan of the MCU, Kingdom Hearts, and Star Wars... this is the story for you! Please enjoy!

Prologue: Time Heist Consequences

"THANOS! I told you. You'd die for that!"

"You should have... You... You should have gone for the head!"

"What'd you do? WHAT'D YOU DO?!"

"Mr. Stark? I don't feel so good..."

"We've been hunting Thanos for three weeks now. Deep Space scans, satellites, and we got nothing."

"When Thanos snapped his fingers, Earth became ground zero for a power surge of ridiculously cosmic proportions. No one's ever seen anything like it... Until two days ago. On this planet."

"Even if there's a small chance that we can undo this... I mean we owe it to everyone who's not in this room to try."

"The universe required correction. After that, the stones served no purpose, beyond temptation."

"Where are the stones?"

"Gone. Reduced to atoms."

"You used them two days ago!"

"I used the stones to destroy the stones. It nearly... killed me. But the work is done. it always will be. I am inevitable."

"What... What did you do?"

"I went for the head."

"You know, I keep telling everyone they should move on and... grow. Some do. But not us."

"Alright. So... five years ago, right before Thanos, I was in a place called the Quantum Realm. The Quantum Realm is like its own microscopic universe. To get in there, you have to be incredibly small. Hope, she's my... She was my... She was supposed to pull me out. And then Thanos happened, and I got stuck in there... See, the rules of the Quantum Realm aren't like they are up here. Everything is unpredictable... What I'm saying is, time works differently in the Quantum Realm. The only problem is right now, we don't have a way to navigate it. But what if we did? I can't stop thinking about it. What if, we could somehow control the chaos, and we could navigate it? What if there was a way to enter the Quantum Realm at a certain point in time but then exit at another point in time? Like... Like before Thanos... The stones are in the past. We can go back and get them."

"We can snap our own fingers. We can bring everyone back."

"I don't know why everyone believes that, but that isn't true. Think about it: If you travel to the past, that past becomes your future. And your former present becomes the past. Which can't now be changed by your new future..."

"Five years ago, we lost. All of us. We lost friends... We lost family... We lost a part of ourselves. Today, we have a chance to take it all back. You know your teams, you know your missions. Get the stones, get them back. One round trip each. No mistakes. No do-overs. Most of us are going somewhere we know. But it doesn't mean we should know what to expect. Be careful. Look out for each other. This is the fight of our lives. And we're gonna win. Whatever it takes. Good luck."

WORLD: EARTH

It was supposed to be simple... go to the past... get all six of the Infinity Stones... return to the present... save everyone Thanos has killed. But then again... there are always consequences when messing with time travel. One way or another. While messing with the past didn't mess with their future... the past... well... that's a different story. A team of Avengers went back to collect the stones. Nebula and War Machine went after the Power Stone. Hawkeye and Black Widow went after the Soul Stone. Hulk went after the Time Stone. Thor and Rocket went after the Reality Stone. Captain America went after the Mind Stone. While Antman and Iron Man went after the Space Stone.

Despite their losses, and unintentionally bringing Thanos from the past to their time, the Avengers were successful. Everyone Thanos had killed had been undone, the Mad Titian himself was dead, and Captain America returned the stones to there proper place in time. However... there was one slip up on getting the Space Stone. One that set up the events to come...

The 2012 Avengers start to make their way out of the building. Future Tony and Scott eye them undercover, the latter, disguised as a S.H.E.I.L.D. agent, went to his coms, "Thumbelina, do you copy? I've got eyes on the prize. It's go-time."

"Bombs away."

Future Antman stated while sliding down to Tonys' Arc Reactor, "Is... is that Axe body spray?"

"Yeah, I had a can just for emergencies. Relax. Can we focus, please?" Future Tony replied through the coms. Future Antman told him, "I'm going inside you. Now."

Just then, Alexander Piece approached the Avengers along with a squad of undercover Hydra agents, "May I ask you where you're going?" Thor replied honestly, "To lunch and then Asgard. I'm sorry, you are?"

"Alexander Pierce. He's the man, one of the folks behind Nick Fury." Tony Stark introduced to Thor. The undercover Hydra agent nodded, "My friends call me Mr. Secretary. I'm gonna have to ask you to turn that prisoner over to me."

"Loki will be answering to Odin himself." Thor told him. Pierce argued, "Oh, he's gonna answer to us. Odin can have what's left. And I'm gonna need that case, that's been SHIELD property for over 70 years."

"Hand over the case, Stark." A Hydra agent told the armored Avenger. Meanwhile, Future Tony whispered to his coms, "All right, move it, Stuart Little. Things are getting dicey up here. Let's go."

"I'm not gonna argue who's got the higher authority here, all right?" The current Tony argued unaware of what Antman was doing...

The ex-criminal asked, "You promise me you won't die?"

"You're only giving me a mild cardiac dysrhythmia." Future Tony told him. Antman paused at that, "That doesn't sound mild."

"I need the case." Pierce told him as Tony argued, "I know you got a lotta pull. I'm just saying..."

"Okay. Then give me the case." Pierce told him. Future Tony ordered quietly, "Do it, Lang!"

"Get your hands off!" Current Tony told the undercover Hydra Agents as future Tony told his fellow time traveler, "Window's closing. Pull my pin!"

"Here it goes!" Ant-Man pulls off Stark 2012's reactor...

...and current Tony drops the case, as he fell to the ground in pain. Everyone went into panic at the sight of Tony, as Pierce eyes widened in shock, "Stark? Stark! Look, he's convulsing. Give him air! Medic!"

"MEDIC! You guys, some help!" Future Tony Stark told called out to the others in the room to help. Pierce asked Tony, "Stark, you... your chest machine?"

Everyone except the captured Loki failed to notice Ant-Man pushes the case to the future Tony Stark, who proceeds to grab the case. As he made off, he went to his coms, "Good job. Meet me in the alley. I'm gonna grab a quick slice."

Suddenly, Hulk pushes Future Tony to the ground which opens the case and the Tesseract slides to Loki. Hulk complained, "NO MORE STAIRS!"

Everyone who wasn't helping Tony runs from Hulk's rampage. Loki saw this as his only chance to escape, he grabs the Tesseract and teleports it away and he didn't care where it took him as long as it wasn't here.

Meanwhile, Thor went up to Iron Man, " You'll be fine, Stark. Stay with us! I'll try something, okay? I have no idea if it's gonna work." Thor uses his hammer, Mjolnir, as the defibrillator on Tony Stark which saved his life. Thor beamed, "YES!"

"That worked a treat. That was so crazy!" Tony got up and smiled in appreciation. Thor laughed, "I had no idea if that was gonna work."

Tony joined in the laughing when he realized something was missing, "The case?"

"The case. It's, uhh... Where's the case?" Thor wondered when he realized that wasn't the only thing missing, "Where's Loki? Loki!"

"That wasn't supposed to happen, was it?" Antman asked the future Iron Man. He groaned as he got up, "Oh, we blew it."

"Loki!" Thor continued to call out to his brother. Unaware that he was already long gone...

WORLD: MYSTERIOUS TOWER

Meanwhile, in a tower far away from the Earth, the former Keyblade Master, Master Yen Sid, sat alone in his studies. It had been only a few years since the disappearances of Ventus, Terra, and Aqua who gave it all to stop Master Xehanort from obtaining Kingdom Hearts. The result of the battle left Ventus in coma with his heart missing, there was no sign of Terra, and Aqua took Ventus to a safe place before going after Terra. She hadn't been heard or seen from since

With Master Earquas dead, and those three missing in action, his former pupil King Mickey was the last of the Keyblade Wielders and Guardian of Light. Xehanort had put the worlds in a dark situation when suddenly a fiery portal opens and a figure steps out of it. The Ancient One smiled, "Good evening, Master Yen Sid."

"Hello, old friend..." Yen Sid smiled in greeting, "What brings you to my home?"

"I trust you sensed the disruption in the flow of time by now..." She assumed. Yen Sid nodded, "Yes, you know the cause?"

"Years from now... Thanos, the Mad Titian, collects all six of the Infinity Stones, and succeeded in his goal in wiping out half all life in the universe. The surviving heroes hoped to use the stones to undo Thanos's work but he destroyed them before they got a chance to use them. The only way they'd ever get to use the stones was to go back in time before Thanos used them. Our time." The Ancient One explained. Yen Sid nodded as he stroked his beard, "I see... so, one of them confronted you for the Time Stone. Did you warn them of the consequences of removing them from the proper time line?"

"I did. I warned them if I allowed this, the stones would be missing this this timeline creating an alternate timeline. However, Dr. Banner promised to put back the stones right before they ever left the time." The Ancient One explained, "I was hesitant at first but when I learn Strange, my replacement as Sorcerer Superme, gave Thanos the Time Stone. I figured there was a bigger play in the master plan."

"He saw something that would allow them to win... then I take it there we're successful..." Yen Sid assumed. She nodded, "Yes, but not without some consequences..."

Yen Sid wondered, "How So?"

"As promised Captain Rodgers returned the stones in their proper timelines. However, Thanos from our timeline, figures out what they were doing and went after them. He never came back. And to make matters worse, there first attempt to take the Space Stone failed and Loki escaped with it." The Ancient One explained.

Yen Sid closed his eyes at this, "In despite their best efforts, it would seem another timeline was created anyways... how bad will the changes in this timeline will be?"

The Ancient One turned to the window and gazed at the evening sky, as she admitted, "Unfortunately... I believe we're going to find out the hard way..."

WORLD:? ? ?

Loki reappeared on a whole new world. When he realized he was safe from both Thanos and the Avengers. He set the Tesseract down and tired to remove the cuffs and face mask. Just then, he heard someone load some short of gun, "Well, well, well... you're the last person we'd except to be here..."

He turned to realize he wasn't alone on this world. He saw he was in the middle a throne surrounded by 13 towering thrones. However, only 8 occupied said thrones. Each wearing a black hooded coat. Loki noticed something odd about them... almost as if they lacked emotion. The one in the second tallest throne aimed his weapon at the Prince of Asgard until the one in the tallest throne simply raised a hand which caused the figure to stand down. Loki assumed that one was the leader. Just then, much to Loki's shock, the leader vanished in a Corridor of Darkness before reappearing in front of him. He then removed his head revealing a man with long silver hair and amber-orange eyes. The man gave an emotionless chuckle, "You're a long ways away from home, Loki of Asgard."

He simply raised his hand as power surge through free Loki of his cuffs and face mask. Loki rubbed his wrists as he replied, "It would appear my reputation proceeds me..." Loki then turned to the man, "I'm afraid you've caught me at a disadvantage... who are you?"

"Nobody of importance..." He replied, "But you may refer to me as Xemnas or Superior."

"So... Xemnas..." Loki started, "I am thankful for you aiding my freedom and I don't want take up any more of your time... so I'll take what is mine and be on my way..."

Loki went for the Teseract however Xemnas was able to pick it up first. He examined it, "My, my... what do we have here... the Teseract we have heard so much about..."

"The one the Red Skull used during Earth's World War II?" The one the sixth throne assumed. The figure on the forth throne stated, "It's still puzzles me of how something of that great power could remain hidden on the world for so many years..."

"Then the Asgardian uses the same source of power to try to conquer Earth in the name of Thanos in turn for the Teseract..." The one in the third throne stated. Loki turned back to Xemnas, "If you know who I'm working with... then you'll hand that back to me... trust me, you don't want to have Thanos on his bad side..."

"The Mad Titian is no more..." A new voice spoke. Another Corridor of Darkness opened as another two figures stepped out of the darkness. One wore a similar cloak the others were wearing while the one in the brown robes Loki could have sworn had no body. The one in the black coat removed his hood and much like Xemnas he too had silver hair only his eyes were yellow and he looked a lot younger. The youthful continued, "He foolishly thought he could go after the Avengers in there makeshift time machine and collect the stones there... but he only met his demise..."

The one in the eighth throne turned to the one in the seventh, "Okay... was there something I missed? Who the mini Xemnas? And why is he with the Superior's Heartless?" The seventh said nothing in response as they continued to watch the conversation. The man with the brown robes stated, "We could not change the events to come but thanks to the Avengers interference with the timeline... we can change things more to our liking..."

"Indeed." Xemnas agreed as his power swirled around the Tesseract before shattering it's shell. Xemnas then pulled the blue Infinity Stone from the glass and held in in his hands, "Loki of Asgard... we have a proposition for you..."

Loki raised an eyebrow, "I'm listening..."

"Help us accomplish our goals and all of you're wishes and desires will be yours." Xemnas explained. Loki turned to him in confusion, "And what exactly are your goals... and if I agreed how do you plan to keep you're end of the bargain."

Xemnas turned to the youthful figure and gave him a nod. With that, he whispered their plans to Loki. The Step-Brother of Thor nodded as he listen to every word and when he listen to the end his eyes widened. He turned to the figure, "You're serious?"

He nodded as Loki stated, "I believed it was a myth..."

"The same could be said for you, your brother, and the Infinity Stones..." The man in the robe stated. Loki nodded, "Touché..."

He then gave it a moment of thought before saying, "You're going to need..." He gestured to the room, "...all you're thirteen..." He went on, "...we also need the seven lights, as the remaining Infinity Stones, perhaps some more allies..."

He turned to the this strange new group, "It'll take time some time..."

"You'll have all the time you need..." Xemnas smirked as he approached him, "So... do you agree..." Loki grinned evilly as he turned to his new allies, "We do we start?"

WORLD: THE WORLD THAT NEVER WAS

(Cue: Hikari/ Avengers theme crossover)

The writers of Spiderfan626 and Is Og Ild proudly presents:

A Marvel, Square Enix, and Disney Crossover:

Staring:

Haley Joel Osment

David Lee Gallagher

Alyson Stoner

Chris Evans

Robert Downey Jr.

Chris Hemsworth

Mark Ruffalo

Tom Holland

Quinton Joseph Flynn

Idina Menzel

Johnny Deep

Daisy Ridley

AVENGERS: WAR FOR KINGDOM HEARTS

Okay... you see why I warned about the spoilers? Okay, the timeline from here on out so I'll give you a brief history of how the events the the MCU had been effected by the timeline...

Events that happened so far:

Captain America: The First Avenger

Captain Marvel

Iron Man

The Incredible Hulk

Iron Man 2

Thor

The Avengers (But the ending change because of the events of Endgame)

Iron Man 3

Captain America: The Winter Solider

Thor: The Dark World (But without Loki involved. Odin is still king of Asgard.)

Avengers: Age of Ultron (But Thor stays on Earth to track Loki in the end and the find the Hulk still on Earth)

Antman

Captain America: Civil War (But Thor and Bruce Banner bring a more peaceful conclusion and convince everyone to drop the accords)

Spider-Man: Homecoming

Black Panther

Antman and Wasp (But Antman's not in trouble with the law, thanks to Thor and Dr. Banner interjection during Civil War)

The events that haven't happened yet:

Doctor Strange (The Ancient One lives a bit longer and Strange doesn't come for training a bit later, the events will happen off screen)

Guardians of the Galaxy 1 2 (Because of the events of Endgame, and due to Strange's request Cap hit the Power Stone on a different world. Gamora returns to this timeline but we will go through the events of the first movie through the story.)

Thor: Ragnarok (While the story will be slightly different, we will go through the events of the movie)

The events that never happened in this timeline:

Avengers: Infinity War

Avengers: Endgame

Spider-Man: Far From Home (Can't wait to see that one)

Mainly because Thanos is dead so the snap never happened. Everyone aged so Peter is in his early 20's in this. But Tony and Pepper still have their wedding and daughter. Oh, and Black Widow and Tony never died. So, that's a plus. :D Oh! And if anyone's wondering, yes, I know Cap's team and Hawkeye's team are like a year apart but I changed it so it all happened the same year...

Now as for the Kingdom Hearts Universe... the only events I can confirm that happened are Birth By Sleep, Union X, and a bit of Dream Drop Distance with Young Xehanort's role. Sora, Riku, and Kairi, never left their world nor was it dragged to darkness because Ansem never went to Riku or Sora. And let's be honest Sora, Riku, and Kairi were never going to get to any world with that raft. It will be mentioned though. So, the three will start the Keyblade journey from scratch, and they will mention what happened when they try it...

Anyways, next time, it takes place years later, the Organization and Loki get their hands on the Reality Stone from the Collector and Ansem and Xemnas use the stones they do have to merge into an all new more dangerous version of Xehanort. One of the Organization members (you can probably guess who) leaves Organization when he learns of the whole becoming Xehanort's vessel thing and warns Master Yen Sid, Merlin, the Ancient One, and a wounded King Mickey (who is badly injured, his world has massively changed because of the new timeline) about what Xehanort and Loki are planning. With the worlds in crisis, the form a team of New Avengers to battle this new threat. But are they right for the job. Find out next time. I hope you enjoyed the prologue. Be sure to leave a review and don't forget to follow and fav. as well. See you next time!