The "Most ambitious crossover ever" originated as a meme, making fun of Avengers: Infinity War and later Avengers: Endgame for being considered as such. Ever since I'm in love at the said meme, I dreamed of making it going full circle by making this very world-collaborative project.
By the way, spoilers from included and/or represented works abound. Please read this fiction carefully.
David, Sora, Mickey Mouse and friends, and Mitra is going in a jungle.
"Whoa, this is the first time I've ever been in the jungle!" David exclaimed. "Before, in my original life, I only saw the jungles from books and newspapers."
"Tarzan tends to swing in the jungle, alright?" Sora asked.
"Sure!" Mickey Mouse replied.
Some time later, Mitra found a blood-splattered map.
"Look," Mitra told everyone. "A map both written and splattered with dried blood."
"That one 'X marks the spot' cliches..." David saw the map.
"Look!" Mickey Mouse noticed. "X marks the spot, let's follow it!
So the group went the way the map guided, completed with David using the phone as a compass. David also scanned the jungle in their way at real-time to make sure they're in the way safely.
The party soon landed on what the X marked. "Yay!"
Only for Antispiral's messengers and Sigma to attack. But...
activates Sandevistan* "Not so fast!" David then pointed Sigma and shot him preemptively on his head.
Sigma is knocked off, and glitched a bit, but then recovered as the Antispiral's messengers appears.
Cross-trivia: Antispiral's messengers are the smallest and perhaps the most insidious Anti-Spiral drones. Made by mixing Anti-Spiral DNA and Mugann components with that of the species they're spying on, the Messengers are deadly infiltrators and information gatherers.
After Lordgenome betrayed humanity in an attempt to save them, all the children he had as the Spiral King were Messengers, leading him to dispose of them the moment they developed enough self-awareness. Nia Teppelin, like all of her late siblings, is also a Messenger, as she discovers to her utter consternation when she's activated.
"Who are you!?" Mitra exposed Sigma.
"I am Sigma." Sigma introduced himself. "And these are Antispiral's messengers, revived by the Sigma Virus." *evil laugh*
"What!?" Sora and Mickey Mouse and friends is shocked.
"You motherfuckers!" David is angry at Sigma and Antispiral's messengers.
"Now, behold the power of Sigma-spiral over-creatures!" Sigma declared, as the Antispiral's messengers ready to combat.
"You must have been bald, scarred,and is manipulative and murderously insane!" Sora pointed Sigma out.
"You guessed it correctly." Sigma confirmed, though his body briefly glitched again. "I was the leader of the pesky Maverick Hunters, but after all that happened, I seeks nothing less than the destruction of the people I was built to protect."
"Very well... You've betrayed the humanity in your world..." Sora responded. "Do you even have any good in you!?"
"I simply abandoned all of it." Sigma responded back. "Also, those reploids... X and Zero... I'll find you!"
"Reploids? X? Zero?" Mitra doesn't even know what reploids are.
"You don't know?" Sigma realized. "That's because you are not from my world."
"Damn right." David confirmed. "Now we're gonna beat up those anti-spiral girls right here and now!"
The group jumped straight to combat against the Antispiral's messengers, except for David who went against Sigma himself.
"Go, go, go!" The group attacks and rise at large, continuously beating and destroying the Antispiral's messengers.
David punched Sigma, but Sigma is all-chrome, making it tricky to hurt him.
"You're all chrome!" David realized Sigma's nature.
"Yes I am!" Sigma then slashes David, but the latter dodged with Sandevistan.
"Sora! Give me elemental!" David told Sora as the latter is combating the messengers.
Sora immediately uses Firaga to burn the Antispiral's messengers down and charges David's cannon. Mitra and Mickey Mouse finishes off the messengers with slashes, while David activates Sandevistan and went behind Sigma while he was trying to slash.
"Burn!" David shoot the flame onto Sigma, burning him.
"That burns...! You're pretty good, but..." Sigma then teleports away.
"What!?" The group as Sigma teleported.
On top of Mitra, Ultron is flying, charging up his beams.
"I am Ultron. And-" Ultron introduced himself.
"Shut up!" Donald Duck interrupted Ultron.
David shot normal bullets to Ultron, but Ultron didn't even flinch or get affected.
"Damnit! He's got Vibranium, the same as with Captain America's shield!" David is frustrated, as Ultron is about to fire the beams.
"Most likely." Sora all but confirmed.
"Die!" Ultron then fires the beams onto the group.
"Nooo!" David then activated Sandevistan and then quickly ran to rescue Sora, Mickey Mouse and friends.
But when David was about to go for Mitra, he slipped and he fell, out of Sandevistan he go. Mitra gets hit by Ultron's beams, leading to an explosion that knocked everyone else out.
"No! Miss Ātman!" Sora cried.
The smokes fron the explosion ensued by Ultron's beams then went out. But as it turns out, Mitra directly resisted the beams and explosion thereof, with moderate discomfort and lack of visible damage (other than chars).
"What?" Ultron is surprised.
"You forgot that I'm a god." Mitra responded. "That cannot kill me. In fact, only gods that's stronger than me can truly kill me."
"Goodness. You managed to resist the my overcharged beams at point blank?" Ultron is frustrated at Mitra. "I overheated trying to push my beams to limit, well..."
David simply had Sora use Thundaga, and then shot the lightning-charged projectile into Ultron. This knocked off the robot, making falling down. The glitch is also there, briefly projecting both Ultron and Sigma at once.
"Uhhh..." Ultron moaned before teleporting away.
"Huh? What's that?" Sora noticed the glitch.
"Could it be?" David wondered.
"Let's move on." Mitra commended. "The treasure isn't there. Let's find it somewhere else."
An iron golem from appeared.
"An iron golem? Sound like it's from... a world with blocks...?" David as he already learned of Minecraft thanks to the phone. "That one!"
A homeless kid appeared behind the iron golem.
"Thank you for saving me and this golem from a trap." The kid thanked the group.
"Blessing from a god?" Mitra responded.
"No problem, kid." David responded.
"I kind of recognize this golem." Sora recognized the iron golem. "It originated from the same world... as a certain blocky man." *referring to Steve from Minecraft*
Note: Both Sora and Steve are two of the DLC fighters in Super Smash Bros. Ultimate.
"Oh, we see." Mickey Mouse and friends replied.
"Where's the treasure?" David asked. "This is a trap, not the treasure we're trying to find."
The iron golem them pointed to the right side.
"Yeah..." The kid responded.
"So... it's on the right road?" David asked again.
"Yeah, literally." The kid confirmed, suggesting the group to go the the right.
"Thank you for your help." Mitra thanked the kid. "I'm a god trapped in another world."
"Bye!" Mickey Mouse and friends, as they, Sora, David and Mitra went to the right.
And so, the group ran in the right road the golem and the kid pointed. They all went further and further into the jungle.
"Just a little more!" David keep running.
"Almost there! We can't give up!" Sora kept running.
"More truth lies beyond!" Mitra kept running.
Not long afterwards, they've all arrived into some illegal area. This area has not one, not two, but three big treasure chest.
"Finally!" David is excited.
The group crossed the barricade tapes (which says POLICE LINE DO NOT CROSS) and examined the treasure chests.
"These are so much larger than typical ones." Mickey Mouse noted. "Is there's anything large inside?"
"I don't know," Goofy replied. "Maybe we should open all of them one by one."
"The chest is heavy as fuck." David noted. "Not that we can't be sure any of the chests have anything on it, as this is also anchored to the earth as well."
"So it's impossible to carry them?" Mitra asked.
"Most likely." David confirmed. "They're both heavy and anchored deeply, so there's no way."
"But where are we?" Sora asked.
"In Dark Woods." David answered.
The group is now inside the Dark Woods. A dark jungle from unknown world, filled with enemies and rubbles from known worlds.
"We're in... the Dark Woods..." Mitra realized.
"Not sure why we go right..." Donald Duck is confused.
"We found the treasures, because we choose correct path." David concluded.
"Oh my gosh..." Sora is surprised.
Mitra nods.
"Wow..." Mickey Mouse and friends are amazed.
"So that's why the kid pointed it out." Sora confirmed.
"I'm not sure if this is a simulation or not..." David said.
"Yeah, but what about the treasure?" Mitra asked.
David then quickly examined the abnormally large treasure chests. He sped up by using Sandevistan. After he's done...
"Let's open it." Sora then opens the treasure chest.
"The treasure is..." The announcer declared... "Rock!"
"I'm back!" A fully cyborg large man appeared out of the chest, carrying a fairly big boulder. "With a rock!"
awkward silence*
"Are you freaking kidding me!?" Donald Duck is frustrated.
"Nope!" The large man denied.
"I remember you..." David remembered something. "Adam Smasher...!"
Note: Adam Smasher is a towering cyborg from Night City, with little humanity left to be seen - not that he ever had much. After being reduced to mush by an RPG blast in the 00s, Arasaka offered him a choice - either pull the plug (as in dying at the hands of Arasaka) or become a full body cyborg. With little to no options and a lack of care for his human side, he accepted and became far more machine than man.
"David Martinez... We meet again..." Smasher remembers David back. He then throws the boulder away.
"Ugh! We found the correct treasure though!" Mitra is frustrated. "After all, two more chests!"
Everyone then approaches the other treasure chest. Unlike the previous chest (the biggest one of them all, contained Smasher and the rock), this chest is much smaller. It's the smallest chest there, but still considerably bigger than an average treasure chest.
"Let's open!" Mickey Mouse and friends shouted, as David opens the chest.
"The treasure is..." The announcer declared. "None!"
Everyone facepalms. Even Smasher, too.
"Damnit!" David is disappointed.
"We got nothing there!" Minnie Mouse is frustrated.
"At least you got me." Smasher said.
"Ok, I'll introduce you my short-while rival." David then proceeded to introduce Smasher for everyone. "Adam Smasher, the fully-cybernetic boogeyman and a hero of the Corporate War in Night City."
"Adam Smasher?" Mitra asked. "The fully-cybernetic boogeyman!? Corporate War!?"
"That 97%-chrome man is a legend to us all. He killed me while both of us was attempting to prove ourselves." David continued. "I did manage to save Lucy and fulfill my past life as an edgerunner. Now that I've been revived by some scientists..."
"Now we're your allies!" Mickey Mouse and Sora days in unison.
"Yeah." David agreed. " Anyways... That story is why I'm a legend nowadays. That's our current treasure, after all."
Everyone then approaches the last chest, which is clearly in between the sizes of the previous two.
"Ok, last one..." Mitra then opens the last chest.
"The treasure is..." The announcer declared. "A crystal! Congratulations!"
"Yes!" Sora rejoiced. "We found a crystal!"
"Yes! The same kind of crystal I found with Mister Arisu!" David exclaimed, though referring to Reiji. He gave a thumb up to everyone else.
"Good job, you fuckable meats!" Smasher congratulated.
"Thanks god..." Daisy Duck thanked.
"What's the crystal?" Smasher asked.
"Let's see..." David then touched the crystal.
"Now..." Sora said. "Somebody's gonna secure the crystal we just found..."
"Yeah..." Adam Smasher then touches the crystal. "And where do we go next?"
"Got it." Mitra then touched the crystal.
"Ok." Sora then touched the crystal.
"Where's the Dark Woods?" Mickey Mouse asked.
Suddenly, someone teleported everyone and the crystal into some ship...
"Welcome to Shin Halberd." A god welcomed the group. "It is like Halberd, but extra dimensional."
Everyone is in Shin Halberd, an upgraded version of Meta Knight's Halberd, designed to dock building-sized mechas, seats for thousand, and for travelling between worlds.
"Who're you!?" Mickey Mouse and friends doesn't know.
"Nice crystal you've got." The god saw the crystal.
"Crystal get!" The announcer exclaimed.
The crystal shows a light that's identical to the light Zero Point has emanated for all of its history prior to the incident.
"This is it." Mitra said.
"There's the Zero Point..." David realized. "The crystal contains the remnants of its full power."
David, Sora, Mickey Mouse and friends, and Mitra learns the actual truth behind Zero Point's destruction.
"Empress Zero indeed burned the Reality Tree..." Mickey learned the truth.
"And then there's Kyuju Kyu and Byaku Shin..." David pointed it out.
"So that's what happened to Agent Jones and some of his friends..." Goofy noted.
"The dead bodies..." Sora noticed.
"Indeed," The god confirmed. "Jonesy isn't the only victim..."
"You're..." Mitra recognizes the god. "The Mercurial Snake!?"
"I'm Mercurius, the Fourth Heaven. And I've got too many reports of the rifts and paradoxes occuring over the past couple of days."
"Got destroyed." Donald Duck hinted, as the group secures the crystal.
"Yeah. I'm afraid to reveal that the Zero Point was overloaded with the burning paradox and the stress, and got destroyed." Mercurius then looked at Mitra. "You're Mitra, the First Heaven?"
"Yes, I am." Mitra confirmed.
A lightning bolt would strike the Shin Halberd as it's close to the danger zone, making a loud boom.
"The remnants of the island are in ruins..." Mercurius sighed. "I'm also trying to find any survivors, yet there doesn't seem to be any. Even the likes of the Hundred-Gods isn't safe from it."
"Alright!" Mickey exclaimed. "Now what's the next step?"