This story takes place near the end of Transformers: Dark of the Moon. This is an alternate ending to the film. This is a one-shot and I have no plans for a continuation.
Transformers: To the End of Eternity
Optimus watched as Megatron blasted Sentinel in the neck. Even if Sentinel was no longer the mentor he knew, he had been a fellow comrade. It was Sentinel who taught him the importance of freedom and justice. He had carried those ideals with him throughout the war. But Sentinel had fallen and lost his way. And the one who had twisted his mentor stood in front of him.
Megatron turned and faced Optimus. "Now it's just you and me, Optimus. This is how it should be. After all, we do define each other. Who would you be without me?"
"Time to find out," Optimus charged at his sworn enemy, raising his axe. As he swung his weapon downward, Megatron blocked it with his right arm and was able to fire a shot to Optimus' leg. As he fell, Optimus tore through his enemy's arm and knocked the shotgun out of Megatron's grip. On one leg, Optimus slammed his axe into Megatron's side. His enemy stumbled backwards and fell to the ground.
"Do not think for a moment that you will be able to sway me the way you did Sentinel, Megatron."
"The thought never crossed my mind. You and I are far better off as enemies. I would much rather have your head in my hands than have you at my side," Megatron sneered. "I can't help but wonder. Why do you still fight?"
"I fight to protect the freedom of all sentient species," Optimus declared.
Megatron threw his head back, roaring with laughter. "Protect their freedom? Such sentimental nonsense. You still don't understand. Power is everything."
"The Decepticons still don't understand that their actions will only lead to destruction. I won't allow myself to let you oppress and destroy other sentient beings."
"Do you believe that we're different from one another? Haven't you noticed how merciless you've become over the years? There was a time where you would capture my soldiers and offer them a chance for redemption. Now you play the role of the executioner. You've changed as well, Optimus. Deep down, you are just as ruthless as I am."
Optimus had nothing to say. What Megatron had said was something he had pushed away from his thoughts. Was he any better than Megatron or Sentinel? How far could he go until he was no better than the Decepticons?
"Even so, I will stand against the Decepticons. Now and forever."
"I wouldn't have it any other way. You've certainly become a worthy opponent, Optimus."
"This will have to end one day, Megatron."
Megatron was silent for a moment. "Yes. It will have to end. But who will be the victor?"
He stared into the eyes of his sworn enemy. For what seemed like eternity, the two had battled again and again. Neither would give in to the other. They both knew that a truce was impossible between them. It began with the two of them and it would have to end with them as well.
A roaring sound grabbed his attention. A Decepticon battlecruiser was closing in on their location. He could see the Decepticons aim their weapons at him. He braced himself for an attack. Even if the situation was hopeless, Optimus wouldn't fall without a fight.
Gunshots flew over Optimus' head, hitting the Decepticons. Optimus turned and saw his fellow Autobots and the human soldier closing in on his location, firing their weapons at the enemy. The Decepticons redirected their attention to his comrades. Attacks from both sides flew in the air. He saw the Deceptions lower themselves, bringing Megatron onto their ship.
"Retrieve Sentinel's parts and retreat," Megatron ordered. The Decepticons picked up Sentinel's body and his weapons, carrying them to the ship. The Decepticon ship took off into the sky. Where the Decepticons were going was anyone's guess. But their plan had failed and they had retreated. The battle was over.
"Optimus!"
"Hang in there, big guy," His comrades rushed to his side. Optimus noticed that Wheeljack was not among them. He lowered his head in a moment of silence for his fallen comrade. Another life loss in this struggle.
"We'll get you fixed up, Optimus," Sideswipe said as he and Dutch lifted Optimus.
Optimus looked at his fellow Autobots, at Lennox and Epps, at Sam and his companion. That was the difference between him and Megatron. His comrades were friends, not tools. He fought for others, not himself. They were brothers in arms wiling to fight for freedom.
He looked up at the sky. The Decepticons would return to wreck havoc on mankind. They had won the battle, but the war was far from over. The Autobots would be there to fight them and protect the planet and its people. Cybertron may be gone, but the Autobots had found a new haven. Earth was now their home, one that they would protect with their lives.
"No matter what the future holds or what schemes you may have, I will stop you, Megatron. We both know it will have to end. One shall stand, one shall fall."
Six months later
How long had he allowed himself to be so weak? To allow his injuries to prevent him from claiming his role as leader of the Decepticons? He would do so no longer. The pain that plagued him since the battle that took the life of the Fallen was now gone. Now he was stronger than before. He was now the true leader of the Decepticons. Just as it was meant to be.
He rose and gazed at his new and improved body. He had not only recovered from the injuries that had plagued him for the last few years, he had enhanced himself. It may have taken parts from Sentinel and most of the energon they had stored, but it was worth it. Sentinel Prime's shield was grafted onto his left arm along with a rifle and his blades were now his to use. He hadn't been born a Prime, but he had become so much more.
Starscream, Shockwave, Barricade, and Soundwave hadn't returned from their last battle. The fools had most likely gotten themselves killed. Starscream was a coward but proved to be useful. Shockwave was competent and had done well in battling the Autobots. Barricade was loyal to the Decepticons and a fierce warrior. Soundwave had been able to provide crucial intel with his abilities. Losing them would weaken the army. To think that they could suffer this much from the Autobots and the humans.
But they were far from finished. They had suffered defeat before in the war. They had always risen from defeat and brought suffering onto their enemies. This time would be no different. The Decepticons would have their revenge.
"Lord Megatron, what is your-" the Decepticon didn't have a chance to finish his sentence as he had his leader's fist slammed into his face. The rest of the Decepticons fell silent, watching their leader with apprehension. Their leader stood there, lost in his thoughts.
Megatron had been killed by a human boy. Megatron had subjugated himself to the Fallen and was defeated effortlessly by Prime. Megatron had been used and humiliated by Sentinel Prime. Megatron had been talked down to by a human fleshling. Worst of all, Megatron had allowed himself to become weak. That would change now. He had been reborn and would no longer be Megatron.
He faced the legion of Decepticons. "Megatron is dead. From this day forward, you will bow to Galvatron."
"All hail Galvatron!" the Decepticons shouted in unison, saluting their leader. Galvatron kept his eyes on his army, a smile plastered on his face. The war was far from over.
"Our battle will resume soon, Optimus Prime. I will show you that I have surpassed even the Primes. Even if it we must battle to the end of eternity, I will have my victory."
Author's Note: After the second movie ended, was anyone else hoping for Galvatron? Before I went to see DOTM, I was on a forum that was discussing it. One poster commented on how they thought it was awesome that Optimus one-shotted Megatron near the end. I thought that that was the most anti-climactic sounding scene possible for the movie. Unfortunately, I wasn't proven wrong.