My first multi-crossover story and a bit of a plot filler. The events of this story happen after the other (mostly unpublished) stories involving TD in worlds other than Equestria. In Equestria's timeline, this story occurs before the Season 6 finale and after "The Return of His Darkness" when Twilight and TD finally confess their feelings towards each other. TD is the main antagonist in this story, but not by choice. How? You'll see, fat Hobbitses.

Disclaimer: I own nothing except for the story and OC's! All franchises and their content belong to the proper owners.

Hope you enjoy!

TD sat upon a throne of darkness, brooding over his plan. It could work, but he would have to gain a massive amount of energy to make it work. But where would he gain such power? He couldn't conjure it up on his own. A sudden thought came to him and he grinned slyly.

"I think it just might work," he said to himself. He snapped his fingers- actually, he can't snap his fingers; he just pretends and his magic makes the sound effect- and a strange being appeared before him. It was yellow in color and pyramid-shaped. It looked to him like Illuminati with a recolor, hat, and bow tie. The infamous demon of Gravity Falls, Bill Cipher.

"Oh boy! Pure weirdness and madness all around me!" Cipher remarked, gesturing about the room. For it was indeed in a state of pure chaos. Floors broke apart and resealed themselves, gravity seemed to be nonexistent, and the walls constantly shifted and changed their appearances.

"Cipher, I need you to do me a favor," TD said, handing him some pieces of paper that had appeared out of nowhere. "Bring these papers to the worlds listed on them and to the beings listed as well."

Cipher's one eye gave him an expression that seemed to be quite cheerful, if a little confused.

"Okay, but if I may ask, why are we inviting them again? After your failed attempts to help them out, I doubt that they will want to come back."

"I know that, so that's why I left something enticing for them should they accept. Besides, it's not like they have it better off the way they are now. Things are looking quite grim for them, and I'm giving them an offer that they can't possibly excuse. I'm also sending my servant to help you with this to spread the word faster."

"That makes sense. Well, see ya later, boss!" Cipher called out. His image suddenly became a 2D triangle with his eye in the center. A bright light engulfed him and he disappeared. TD sighed and lay back on the throne. If this all played out properly, he would no longer have to worry about his brother's meddling. Only one thing worried him. One of the worlds in mind had the love of his unnatural life living there. How would she take this? It would break her heart...

"It won't matter," a voice said in the back of his mind, "Think of the bigger picture! No more restrictions! No more competition! It will all be yours."

TD seemed satisfied with this answer and smiled some more as he sat back on the throne.

Dr. Eggman sulked in his easy chair after his most recent defeat. He groaned as he recalled some of the past events. Sonic had been bad enough to deal with, but now that meddling fox had been released as well. With him on Sonic's side, there was not much he could do to fight back. Bill Prower was simply too powerful; he had even managed to defeat his employer's greatest invention, Metal Prower, who had been specifically designed to defeat Bill. Eggman grimaced as if in pain.

"Oh, why even bother?" he moaned. "I might as well hang up my career for good. There's nothing to do."

"Excuse me, boss," Orbot said as he came into the room, waving a piece of paper in his hand. He was followed closely by Cubot.

"What is it?!" Eggman hollered, "I told you not to disturb me!"

"Forgive me boss, but you have a message from someone. Someone you know."

"Eh? Let me see that!"

Eggman took the paper from Orbot and read its contents. A look of surprise, then glee appeared on his face. He then sat up straight in his chair and ordered, "Prepare the teleporter, boys! We're going to visit an old friend."

"But aren't we going to be using that for the next invasion, boss?" Orbot asked.

"We have a teleporter?" Cubot asked excitedly.

"There's been a change of plans," Eggman replied, "A big change of plans."

Eggman began to laugh in his evil manner, confident that this time, he would not be stopped by anyone. Especially Sonic and Bill Prower.

The centaur known as Tirek sat glumly in his cell within the depths of Tartarus. It was so infuriating to him that he could be defeated so easily by those pitiful ponies. He would need to think bigger next time, and next time, he would destroy that Princess Twilight. His guard, a three-headed dog similar to Cerberus suddenly growled as a mysterious figure appeared before them. He was different from anything Tirek had ever seen before; his entire image was covered by a blood-red cloak and robes, and he was walking on two legs instead of four. The guard growled menacingly at the figure, but the figure simply raised a hand. The hand was covered by a steel glove that looked cruel and intimidating. A burst of magic came from the figure's hand and the guard dog was struck in one of its faces. It suddenly went limp and fell to the floor. The figure turned to Tirek, revealing an opening in his hood, but no face could be seen inside.

"My master, the Terror of Dimensions, sends his regards," a dark and cold voice emitted from the figure. He tossed a stone into Tirek's cage and disappeared in a fiery blaze. Tirek was confused, but he picked up the stone anyways. The stone had red lettering on it, which said "Throw at cage." Triek threw the stone at the bars of his cage and the stone turned into a swirling portal mid-air. A magical stream exited from the portal and was absorbed into Tirek, making him slightly bigger and stronger.

"Enter," a voice said coaxingly from the portal, "And all your desires will be granted in due time."

With nothing better to do, Tirek obliged, the portal closing behind him upon leaving.

The Overlord was floating broken and distorted in an empty void. He had been defeated quite recently by the Ultimate Spinjitsu Master, who had only previously been the Green Ninja. The Overlord bit back a curse. The boy was strong, and so were his friends. Even with his employer's help, they had been decidedly defeated. But they wouldn't last long. He would return and he would have his revenge. But for now, he would wait. He was patient enough to wait for as long as it took. Just then, the Overlord found himself in a spiritual form and a single figure stood before him, one unfamiliar to him. However, the power radiating from him was greater than even that of the Ultimate Spinjitsu Master.

"Ah, there you are!" Bill Cipher said as he stared at the Overlord. "I was wondering where I'd find you. My master has sent me here to give you another chance at revenge."

"Who are you? Why have you come?" Overlord asked.

"The name's Bill Cipher, but you can just call me General of the Armies of the Terror of Dimensions! ATD for short!"

"Tell me then, why would I accept his help? He has proven worthless to me!"

"To be fair, you kinda tried to betray him," Cipher noted. "Besides, I could just leave you here. You'll have a long wait before you can do anything."

The Overlord paused for a moment. It was true. He would not be able to do much and who knew how long he would be forced to wait before he could regain physical form again? He growled and said, "Very well! I will come."

"Great! Hold onto your hat!" Cipher stated as he took off his hat. The hat grew larger and larger until it was big enough to cover the two of them entirely. Which it did, of its own accord. It then disappeared, along with the two evil beings.

The Gravemind of the Flood rested within the depths of a Halo ring, going over the events that had recently occurred. Not long ago, an Elite had made a deal with him and had given him High Charity and the nearby Halo ring to infest and destroy all he desired, so long as he spared a few particular figures. He had honored their agreement, but now some time had passed without much to do. He had been reduced to almost nothing temporarily by the Arbiter and Master Chief. They had destroyed the majority of his form while he had been trying to rebuild himself on a Halo ring. He had managed to escape, but not without much harm done to himself. Now, he rested in an almost dormant state, waiting for a moment from which he could intervene. Just then, an Infected Covenant Banshee flew into the corridor, badly damaged. It dropped a small box from where someone would rest in the cockpit and crashed into the ground, exploding. The box opened up as it hit the ground and a piece of paper flew out. The Gravemind grabbed the paper out of curiosity and stared at it for a moment. Then, it looked at the box and saw a button on it. He pressed the button with one of his tentacles and a portal opened from the box. Gravemind dragged his body through the portal and disappeared through it.

"Well, I hope that everything is to your liking?" TD inquired, looking at all of the villains before him. They were all gathered around a large dining table TD had prepared for them. Each had been provided a different delicacy to enjoy. Bill Cipher was eating a globe with a glass of wine to sip on; Gravemind was consuming some fresh corpses nearby, though he thankfully did most of it out of sight from the rest of the group; Eggman was having a large pot roast; Overlord was in a more human-like form with a dragon head, eating pure darkness; and Tirek was consuming streams of magic from some liquid vials that TD claimed were full of "Liquid Magic". TD himself was eating from a bowl of popcorn and occasionally sipped from a glass full of lava. A silence had fallen upon the room and a cricket's chirping was heard. Everyone glared at TD, who shrugged and said, "Sorry! I couldn't resist!"

"Enough of this!" Tirek finally snapped. "Why are we here?"

"Yes, explain why we are here," Overlord agreed. "Why listen to the one who has only ever delivered us empty promises?"

"Says the guy who betrayed him at the last second!" Cipher pointed out. "Had you simply kept your end of the bargain, you wouldn't have had any problems!"

"True," Eggman agreed, "and he technically never did anything to provoke us. But hey, can you blame us for being a little selfish?"

"Actually, yes."

TD raised his hands and all fell silent once more.

"The reason I have brought you here today is to discuss a daring plan. I wish to attack and destroy my worst enemies, but I can't do it alone. The energy required will be too much for me to harness and fight off those who would oppose me at the same time. So, that's where you come in. Help me, and I will give you all that you desire."

The crowd was silent, so TD started to play on their hopes and desires.

"Think about it: None would stand against the mighty Lord Tirek; Weirdmageddon would become a world-wide reality; Eggman Land will finally come to be; Ninjago will be consumed in darkness; and the Flood will consume all! All this, and more I can grant you, if you join me."

The villains debated among themselves, and it was Gravemind who spoke next.

"If we are not cautious in our actions, there is a possibility that they will defeat us all too soon. We must divide and conqueror if we are to gain the time needed to proceed."

"You speak the truth, Gravemind," TD nodded. "I only wish that the Prophet of Truth had possessed your wisdom. So, have we got ourselves a deal?"

The villains all cheered or nodded.

"Good. Cipher, start us off."

"It's a DEAL!" Cipher's voice boomed, echoing through the room. His hands were engulfed in blue flames, signifying the importance of the agreement. The villains all shook his hand, including TD, and separated. The deal had been struck; there was not going back.

"Now then," TD said cheerfully, "Let's start with the invasion forces..."

A red blur rushed through the Emerald Hill Zone, followed closely by a blue blur. The two blurs rushed over to a cliff side and the blue blur jumped into the sky and brought itself down on the red blur. They stopped as a result, revealing two anthropomorphic creatures. One of them was a blue hedgehog with red running shoes, the other was a red fox with blue running shoes. Both wore white gloves over their hands. The fox was on the ground laughing.

"Okay, okay!" the fox giggled. "You win, Sonic! I give!"

"Bill Prower, that was not cool!" Sonic shouted at the fox. "I could've drowned!"

"So I teach you how to swim. Big deal!" Bill replied. "Besides, the water wasn't that deep and I am perfectly capable of saving people from drowning. I did serve as a lifeguard once, did you know that?"

"Just, don't that again without a fair warning!" Sonic complained.

"Oh, come along," Bill said calmly, lying back on the grass. "You know that you wouldn't have gone in voluntarily."

Sonic opened his mouth to argue, then realized that what Bill said was true.

"Eh, you got me there," Sonic agreed. He helped Bill to his feet.

"Thanks. Now that that's over and done, have you Miles today?"

"Come to think of it, no. I haven't seen Tails for the last couple of hours. Probably working on another project of his."

"I don't know. Something just doesn't feel right. I got a feeling that something bad is about to-"

Before Bill could finish, the entire ground shook violently, causing Sonic and Bill to almost lose their footing. Bill then clutched his head as a vision came to his mind. He saw Tails being dragged by a strange looking group of warriors, human in appearance but with mechanical weapons and gear. They stopped before one who seemed to be the leader. The leader took a good look at Tails and brought a gun to his head. Just when he fired the shot, the vision ended. Bill looked to Sonic.

"Miles! In trouble!"

Bill took off at full speed down a hill, achieving Mach Speed in under a second as he raced off in search of his nephew. Sonic didn't waste a minute and followed in hot pursuit, calling on his coms units as he did.

"Guys, we got a problem!"

"So, why did you call us all here, Nia?" Kai asked his sister, as they surveyed the image shown before them. Nia showed an image on the computer screen nearby as she informed them on what she had found.

"A ship has been spotted headed down towards Ninjago City. It seems to be in the middle of a crash landing. I've tried contacting the pilot, but there's mo response. The ship is headed straight for Ninjago city! The mayor has requested that you guys check it out."

"We're on it!" the Ninja shouted. They rushed out of the room and into a special garage where several motorbikes were stored. They leaped onto the bikes, revved up the engines and drove towards the city at full speed. It didn't take long for them to find that the ship had crashed somewhere in the city during their drive. They were stopped by some police officers and military once they entered the city. The mayor was with them.

"It's the Ninja! Thank goodness you've arrived!" the mayor exclaimed. "The ship has crashed in the square! We sent some teams to investigate, but something attacked them. It's starting to overrun the city!"

Just then, a loud screeching was heard and a strange corpse-like figure appeared nearby: a Flood Combat Form. It roared and charged at the mayor, but was quickly sliced apart by Kai's sword. They didn't get the luxury to rest, however.

"I sense that there's more of them coming!" Zane shouted in warning.

"Then let's get ready to kick some butt!" Cole shouted as he and the rest of the Ninja prepared themselves. A huge swarm of the parasitic creatures appeared from around the corner and charged at them with a howl.

Dipper and Mabel were expecting another enjoyable summer with their great-uncles, Stan and Ford Pines that day. Not to say that they expected the summer to be normal; Gravity Falls usually was anything but. There were still magical creatures that lurked around the town, some of Bill Cipher's weirdness had yet to wear off, and even the townsfolk were a little odd in their own rights.

That being said, seeing the area under attack by a thirty-foot tall centaur was the last thing they had expected. Their bus driver had pulled over with a jerk as soon as he had seen the destruction and had tried to leave the area, but the barrier around the Falls suddenly refused to let them leave. Dipper and Mabel were freaking out, but they did manage to compose themselves enough to try and find out where their uncles were. Thankfully, they didn't have long to wait, as the people in question rushed up to them.

"Dipper! Mabel! You need to get out of here!" Stan shouted.

"Gruncle Stan! Gruncle Ford! What's going on?" the twins asked.

"Probably one of Bill's friends," Ford replied. "You need to leave Gravity Falls now!"

"We can't!" Dipper stated. "The barrier, it won't let us leave!"

"Fleeing is not an option!" the centaur called out, not specifically at them but to all of Gravity Falls. "My master has placed a powerful spell on the barrier that encases this town! Now, bow down to the power of Lord Tirek and despair!"

"Chief! Wake up!" Cortana shouted. The Chief awoke from his cyrosleep chamber and asked, "What's wrong?"

"We're under attack! An army of robots just attacked the base with some madman. They're already on our doorstep! Get downstairs, now!"

The Chief didn't waste a minute as he opened up his hatch from the inside and grabbed a nearby rifle. He took an elevator down to the docking bay where the fighting was beginning. What Cortana had said was right. An army of robots were attacking a squad of Marines and ODST, mercilessly plowing through their defenses. Most of the robots looked a lot like animals of some kind, and each seemed to have a different role to play. The Chief lifted his rifle and fired away into the robots. They were easily destroyed, although some had some kind of special defense to prevent immediate destruction. A few robots looked more human-like and only used melee attacks, but their combat features were enough for the Chief to stay occupied for a brief moment when engaging them. As the Chief kept fighting, a large robot dropped into the docking bay. It was shaped to look like some kind of obese figure with a large moustache and a creepy smile. It was red in color, with yellow edges and blue eyes. It's only known means of attack was to either fire its spiked arms at the Marines and have them return after firing or to throw bombs out from a pack on its back, which also seemed to double as a jetpack. It occasionally used the jetpack to fly as high in the air as the docking bay would allow, then crash down upon the Marines. None of the Marines' weapons seemed to damage it. The top half of its face opened up like a hatch to reveal the cockpit and a fat man sitting in the cockpit.

"Ho ho ho!" Eggman laughed. "Look at you! Fighting as if you actually have a chance to win! Resistance is futile my friends! Bow down to the might of the Eggman Empire!"

Eggman laughed again and closed the cockpit to his Death Egg Robot, revving its engines as he stared in the Chief's direction.

Twilight Sparkle had literally just gotten out of bed to greet her coltfriend, only to discover that he wasn't even in the room. This was odd to her, as he usually never left her room until after she had decided to wake up. He claimed that he just liked to see her sleep, because she looked cute, but she knew that it was just an excuse to see her just a moment longer before taking off, even if that excuse was technically true. She shrugged it off, thinking that maybe it was just a one-time thing. Maybe he was out on official business. She walked outside her door and nearly freaked out when she saw Discord in front of her door.

"Oh good! You're awake! We've got a problem," he said bluntly.

"What kind of problem?" Twilight asked, rather annoyed to see him.

"How about a 'We are all going to die' kind of problem?"

Twilight's eyes widened and she said, "Get the girls! Meet me here when you-"

But Twilight never finished her sentence, for right when she spoke a loud boom was heard outside. She rushed past Discord and out onto the balcony of the castle in time to see a large x-shaped tear in the sky. She recognized it to be a rip in time and space. A triangular form appeared from the portal, laughing like a maniac.

"Oh, it's happening!" Bill Cipher shouted, as he took a physical form. "It's finally happening again! Physical form? Don't mind if I do!"

The sky turned into a strange color and the entity grew to a massive size. Twilight was startled at this creature's appearance, too surprised to react properly.

"Oh no!" she exclaimed.

Unknown to all of these beings, their worlds and universes had been joined together by the powers of Chaos and their worlds all became one. A single portal appeared at the center of this chaos as a dark voice laughed in triumph.

"And so it begins," the voice remarked, signaling the start of the events that would follow.

Well, there you go! The first chapter to my multi-crossover story!

I originally planned to finish the other stories that explain TD's original involvement in each world/universe brought into this, but couldn't hold out any longer. The stories will still be coming eventually, but mainly to fill the gaps now.

Hope you enjoyed! Cya next time!