"Another betrayal? Come on Eggman, haven't we gone through this enough?" Sonic asked.
"Are you really that surprised, Sonic?" Robotnik asked.
"Surprised? No. Disappointed? Yes," Sonic replied. "I had really hoped that you would have waited until everything was fixed before stabbing us in the back, but I guess you're not known for being patient."
"You would be correct in that regard, rodent. Now then..."
The light that was holding up Sonic vanished, dropping Sonic to the ground. Eggman then floated into the air on his machine, glaring down at Sonic as chaos energy swirled around him. "It is time to finally finish this. You and me, one last time. And when I've beaten you once and for all, I will recreate the multiverse. A multiverse in my image. And one without you."
"And what makes this different from the six or so other "one last time" battles we've had throughout this adventure?" Sonic asked. He needed to keep Eggman talking, give himself some time to regroup. After the stunt Sonic had just pulled with the Chaos Source, he didn't have anything left in the tank. Eggman had the full might of the Chaos Source, had Sonic's friends hostage and had managed to keep his wits about him. Things didn't look good.
"What makes it different, rodent, is that I now hold all the cards. Absolute power, your precious friends and, as always, the intelligence advantage," Robotnik replied. Then a wicked smile spread across his face as he glared down at his greatest foe. "But that's never stopped you in the past, has it? There's always a way to win so long as we try. That's what you've always said. Well then, go on Sonic. Try."
Beam of chaos shot from the machine, annihilating where Sonic had been just a moment earlier. Sonic skidded to a stop behind the machine and tried a spin dash, but he bounced off a barrier and fell to the ground. He landed in a roll that rocketed him away from pillars of chaos that tore apart the area around him, just barely managing to get out of the way.
"Got to...try to...help," Twilight grunted. Her horn started to glow for a moment, but then the light faded as Eggman snickered at her.
"Don't waste what little energy you have left. You're spent, princess. Wasted everything on fighting Sombra. Here's some free advice. Learn to pace yourself, or else you burn out before the real fight starts. And speaking of burn outs..."
Eggman created a sphere of chaos around Sonic, who started to look around for a way out. The sphere started to compress, and Sonic slammed himself into the rapidly shrinking walls in a desperate attempt to free himself, but to no avail. Eggman cackled like a lunatic as the walls closed in on Sonic, about to crush him into nothingness...only to gasp with shock as Sonic was teleported out of the barrier. Eggman snapped his head towards his captives, finding that Discord had been the one to save the hedgehog.
"Defiant to the end, eh Discord? Fine, you can be the first to perish!"
Discord screamed in pain as the tendril in him began to drain him of his life force, using him to fuel the machine. Fluttershy and the others tried in vain to get to him, but they were all far too weakened to help.
"Don't worry Discord, your power will go to good use fueling my machine to...y'know, I really should give it a name. How about the Chaos Theory? Oh, I like that," Robotnik chuckled. A blur of blue slammed into his barrier once more, getting Eggman to turn his attention back to the fight. "Didn't feel much impact from that one, rodent. Running out of steam?"
"Come on Eggman, you've been at the game long enough to know that it's considered rude to destroy another annoyances when you're fighting with your biggest threat," Sonic joked, though he was struggling to catch his breath. "If you're not going to really try and destroy me, then I might as well go home."
"You are right. How rude of me Sonic. Since this will be the last time I see you...I should really put my all into destroying you!"
Eggman stopped holding back and unleashed the full power of chaos. Explosions that ended pockets of the time space continuum. Erasing reality and creating null zones. Shattering time and hurling it at Sonic. He held nothing back. It was only thanks to Sonic's incalculable speed that he managed to stay ahead...and even he felt himself starting to slow down.
"Soon, rodent. Soon it will all be over," Robotnik taunted as Sonic just barely dodged another retcon blast. "You've pushed me to my limits. You've made me create and think in ways I never would have dared. And you even made me team up with others. But now, finally now, it ends. And it ends the way I always knew it would. With you failing. With you losing. With you being just. Too. Slow."
Any comeback Sonic could have answered with died in his throat as a blast ripped him from his feet and sent him tumbling across the ground, where he lay. He struggled weakly to get back to his feet, panting heavily as he gazed up at Eggman who was glaring down at him.
"It's over," Robotnik said.
"Not while I still breath," Sonic replied.
"Then let us remedy that."
Sonic took off again, but Eggman could see him now. Could keep track of him. And with a wicked smile, Eggman knew it was over. He had finally won.
"So this is how you're going to let it end? Going out like a wimp while Eggman get's to destroy everything and become the new ruler of the multiverse?"
Eggman glanced over his shoulder with some surprise to see that Rainbow Dash had spoken. She was clutching at the tendril of light that was digging into her chest, but there was still hope in her eyes and defiance on her face.
"I'm trying my best here, Dash," Sonic said.
"Trying to bolster his spirits, Rainbow Dash?" Robotnik asked. "How cute. Pinning all your hopes on him shows what a fool you truly are."
"Because honestly, I thought better of you. I thought that you were supposed to be the best, the greatest. But you're going to fail. Just like you always do. Ha. Guess you aren't so amazing after all. I'm ashamed of myself for every thinking you were somepony to overcome."
"Okay, ouch Rainbow Dash."
"Rainbow, what's gotten into ya?" Applejack asked.
"You've just proven what we've always known about you. Weaken, stupid and even when you're on the cusp of victory, you somehow manage to find a way to fail. It's no surprise nopony ever cared to remember you or think of you. And then you got here, and you finally got your chance to prove to them all that you are somepony amazing...and you blew it. I shouldn't be surprised."
"What are you talking about?" Sonic asked as he barely avoiding being retconned. "Plenty of people care about me!"
"But hey, if these words sting, if they fill you with rage and resentment, then prove me wrong. Show me that you're something more than a failure. But I doubt you will. Since failing is what you do best."
"Um, Rainbow?" Applejack asked. "What are ya talking about?"
"What indeed? These aren't words of encouragement. They are the ravings of lunacy," Robotnik said. "If you are trying to bolster Sonic's spirits, you should pick your words better or at the very least try to tell him he's slow, or something. Is this your first time insulting the rodent? Because I have some great insults if you wish to borrow them?"
Rainbow Dash then began to laugh. A hollow, joyless laugh, but one that sent shivers up Eggman's spine.
"That's the problem with you, Eggman. It's all about Sonic. Sonic, Sonic, Sonic," Rainbow Dash chuckled. "This may be hard for you to comprehend, but...I wasn't talking to Sonic."
"What?" Robotnik asked. "Then who could you possibly-"
"IT'S MINE!"
Eggman screamed in fear as the smoldering body of Sombra slammed into him, the dark king roaring as he tried to wrestling the control of the Chaos Theory away from Eggman.
"Give me back my power!" Sombra roared.
"How in the hell are you still alive?!" Robotnik asked.
"Sonic! Now!" Rainbow called out to Sonic. Sonic smirked as he caught on before spin dashing through the tendrils that were holding his friends in place. They all weakly fell to the ground, with Sonic catching Tails while Rainbow Dash caught Applejack.
"You knew Sombra was still alive?" AJ asked. "But how?"
"Come on, do you know how many times we've killed him and he's come back? I doubted that chaos rending his body would put him down," Rainbow chuckled. Then the four of them glared up at where the two villains were fighting for control over the Chaos Theory. "Alright, I've done my part. What's the plan?"
"Get me to the power source of that machine and I can fix all of this," Sonic said.
"Then we have a plan. Let's go!" Tails said.
Tails grabbed Sonic and Rainbow grabbed Applejack, the four of them flying towards the villains. In unison the fliers hurled their carry on towards the villains, who stopped fighting just long enough to notice the hoof and fist right before they took it in the face. Eggman and Sombra plummeted towards the ground while Sonic and AJ landed on the Chaos Theory.
"Here it is," Sonic said as he finally found what he was looking for. He ripped off a panel to find the emerald that had been carved out of the Source. He picked it up and held it for a moment, able to feel the full weight of chaos.
"And that can fix everything?" AJ asked.
"Yes. With this. It can all be fixed," Sonic said with a smile. He then closed his eyes and started to concentrate, taking on the full power of chaos. "It's been a fun ride everyone, but now it's time to-"
Two lasers fired through the air, one from a gun and the other from a horn. Rainbow Dash, with her insane reflexes, was able to move fast enough to tackled both AJ and herself out of the way of the first one. But Tails, who didn't quite have her speed and reflexes, could only throw himself in front of the second one before it could hit Sonic. And as Sonic looked over his shoulder, he had to watch as his oldest and best friend was atomized before his very eyes.
"Eight," Robotnik said with a smirk. Rainbow Dash and Applejack were on the pair in an instant, Rainbow caving Sombra's head in with a kick while Applejack broke Eggman's arm with a buck.
"Eggman...you..." Sonic seethed with rage.
"Go ahead Sonic, rewrite reality! Fix everything! Send it back to how it was!" Robotnik laughed. "But know that your friends will never be safe. Because so long is there is a Sonic, there will be an Eggman there to try to kill him and his allies. So recreate everything! Bring all your friends back to life! I can't wait to kill them all again."
"I could erase you," Sonic whispered.
"But we both know you won't," Eggman replied with the widest smile he could make.
Sonic wanted to. It would be so easy. Just use the Chaos Force to fix everything, to erase Eggman and repair the world. But he knew Eggman was right. So long as there was a Sonic, there would be an Eggman. And so many other threats. His world deserved better. His friends deserved better. He took a moment to look over at where the others were, where the Freedom Fighters were. They had gone through so much with him. They deserved a happy ending.
"Sonic?" Sally asked. "What are you doing?"
Sonic felt himself smile despite himself. She always knew what he was thinking, even when he tried to hide it. She was the best. And she deserved the best. Which was something he could never give...until now.
"What am I doing, Sal? What I always do. Save the worlds," Sonic said. Then he glanced over at the ponies and winked at them. "You guys were pretty cool. Thanks for all the help. And don't worry. I'm going to fix it all. You'll never have to worry about keeping your world safe ever again. I promise."
"Sonic...no...NO!" Sally yelled.
Sonic then locked eyes with Eggman, who was staring up at Sonic with fear in them. And Sonic smiled.
"Sonic and Eggman. Two sides of the same coin. Two parts in the equation. But remove one of those...and you remove the other. It's basic science, doc."
"You're...you're insane," Eggman whispered.
"And you just now figured this out?" Sonic chuckled. "Doc, I thought you were supposed to be smart."
"Rainbow, stop him!" Sally ordered.
Rainbow kicked off fast enough that light shattered around her, reaching Sonic in a moment. But as fast as she was, Sonic was just a bit faster. Fast enough to say one last thing.
"Thanks for the good times, Rainbow Dash. It's been fun. Take care of them. For me," Sonic asked.
"I will," Rainbow replied.
"Thanks. Chaos Control."
And everything went white.