In the Pentagon, several Reanimen were hammering away at what looked like an Invincible, but with a different style of clothes. Reanimen are corpses of dead soldiers that were collected by the Global Defence Agency and then given to D.A. Sinclair to be enhanced beyond human means, in an attempt to have them serve humanity one final time. The different-looking Invincible was one of Mark's infinite alternate versions from a different dimension that had been brought to this one in order to cause as much destruction as possible.
"Okay, stop. He's dead."
Cecil Stedman, director of the GDA, says. Next to him stands his second in command, Donald Ferguson, who was an enhanced human-android. Blood is all over the hall, and many destroyed Reanimen lie across the space. Both Cecil and Donald are injured, with Donald missing almost half of his upper right body.
"The team thinks they're from alternate dimensions where Mark isn't so... Mark," Donald says, marking on the fact that their Mark is a good young man, who tries to do good.
"No shit. And there are how many of these nightmares out there?" Cecil asks.
"At least 18. Reports are still spotty, but they seem to just be destroying whatever they can. No pattern or plan that we can detect." Donald tells him.
"So no way to predict what they're gonna do next, either."
"There is some good news, sir. This Invincible wasn't as strong as ours." Donald tells his boss.
"Then maybe we have a chance. Then again..." Cecil looks at the hallway and the amount of destruction just one of the alternate Invincibles did. He has nothing to counter that, not even the specially created frequency they discovered that hurt the invincibles was going to do much, if they didn't find a better way to use it offensively.
"Start the boys making more of those noisemakers and get the room back up and running. We need to respond, and we need to do it fast. From what I could see, they are killing many and more are to come." Cecil says.
"Sir... the engineering wing is gone. And how exactly do we respond to this?" Donald asks.
"I make a call."
"You mean, calls, sir?"
"No, call, singular. Just one."
"To whom?" Donald asks.
"The Sentry."
.
We turn back the pendulum for several decades, when the world wasn't that different, but a bit less extreme, to a time when the world's greatest hero was the Immortal, who had been around for millennia. But we go further, out of the Invincible Multiverse and into an entirely different Multiverse, the Marvel Multiverse. In Western Pennsylvania, two men have just stumbled into a laboratory looking for drugs, for meth works. One of them is an addict, a junkie and accidentally found the laboratory, which was meant to be secret. As he walks through it, he finds a series of liquids. And one of them was a strange, bright serum.
{Do not touch. Project Sentry.}
Reading the label, Robert Reynolds can't hold himself back. He grabs a chair and smashes the display case.
*CRASH*
He grabs the serum and smells it. His senses are overwhelmed, and for a brief second, he feels as if he has reached the best high in his life.
"Whoa."
"What is it?" his partner asks.
"Don't worry about it," Robert says, unwilling to share his find.
"I want some."
Before his partner can reach him, Robert downs the entire vial in one go. An untested and experimental adaptation of the Super Soldier Serum, is drunk by a meth addict, by stumbling upon it by chance.
"Dude!" the partner shouts in anger.
But a moment later, his anger turns into confusion. Robert starts to convulse in pain and experiences muscle spasms. His eyes shine in yellow light, and he tries to take a single breath.
"AAGGH!!"
"Dude?!"
"NGGAA!"
Robert falls to the ground, shouting in pain. In desperation, a small vial appears next to him. He takes it without thinking about it and downs it as well. Right at that moment, two guards appear at the door, pointing their guns at Robert and his partner.
"Hands in the air!"
"We have a break-in! Building nine. Th-The lab. Over?"
"In the air!" the policeman shouts.
"AAARRRHHH..."
*BBBBOOOO---OOOOOOOOOOMMMM*
With Robert at its epicentre, the entire complex explodes, killing his partner, the two guards and several scientists who worked in the lab and those adjacent to it. A large area is levelled as Robert was imbued with what the Professor called: 'One million exploding suns'. The police arrive, and after them, so does the Professor, who created the serum in the first place.
"Oh, my. Oh, my. Oh, my. Oh, my," he says, looking at the wreckage that used to be his lab.
At that moment, from below, a large chunk of the debris, Robert, appears. His appearance has changed completely. His hair, which was short and blonde, has grown long, but not only that, it has changed colour and is now pitch black. He looks around as if he doesn't know where he is and is confused. But the confusion disappears so fast that it might not even have been there. His mind clears, his thoughts start to race and speed up so fast that if there were someone who could read his mind, which is no longer possible now, he or she would go insane immediately. He remembers the moment before the explosion, another vial with unknown contents... that's what it was. He remembers seeing small words on the side of the vial — the Essence of a sound mind and soul. And Robert can feel it, feel the effects.
His mind is cleansed of all mental maladies, from boredom to addiction to even insanity. He knows that he will no longer be affected by such issues for the rest of his life.
A natural mental shield now surrounds his mind and protects him from outside influence. No matter how powerful or skilled they are, no one can affect his mind against his will. He doesn't know it for certain, but he understands just how powerful and useful this is. But that's not all. Robert, who was average as they got, now has his mind enhanced. Not only by the Golden Sentry Serum, he drank, but also by the second one, the Essence. Robert now possesses a genius-level intellect with a perfect memory, archiving, indexing, instant recall, fully retroactive, with protection from harmful memories.
Finally, similar to his mind, his soul is cleansed of all maladies and has become a bulwark against spiritually based afflictions. He is completely immune to soul attacks, manipulation, destruction, and so much more. Robert has been blessed with a perfect balance between his mind and soul that cannot be broken or lost. This balance protects the core of his being, thus granting him both infinite willpower and protection from personality death. Nothing can make him falter, and he will never lose his sense of self through events such as apotheosis or reincarnation.
Robert looks at the Professor.
"Was this your lab, sir?" he asks.
"Yes... that was my life's work," the Professor answers. "But now it's... it's..."
"I apologise for this," Robert says.
"It's alright... I suppose I can rebuild," the Professor says.
"That's not what I meant," Robert says.
"Wha-"
The Professor turns around to Robert and suddenly has his neck inside Robert's hand. He feels great pain and looks at Robert in fear. Seeing the fear, Robert doesn't change his mind and goes through with it. Having felt his massive psionic abilities, Robert makes use of them. In the span of a yocto second, he erases everything concerning the Golden Sentry Serum, Robert Reynolds and the research he did. It was the best he could do without killing the old man, as that would have been a bit much in his opinion. The man was innocent after all, even if not as innocent as one might believe. To acquire his knowledge, he didn't just do good things.
After he is finished, Robert flies into the sky. Not much went as well with his powers as the Essence he had somehow acquired. His beyond-genius intelligence and perfect harmony between his mind and soul were perfect in keeping a calm mind and understanding his situation better with each passing moment. With every second that passes, he understands and realises his powers better and knows how to use them effectively.
The powers he has acquired derive from the Golden Sentry Serum. The Sentry is the name the Professor gave the project, so he shall honour this at least. Robert has come to understand that the serum has created a phase shift in his molecules, causing him to become partially out of synch with reality. He understands that there is something special about his existence, as if there were no ceiling or upper limit to what he could potentially do. He had to use his powers unconsciously, to keep his form stable, he had so much power contained inside him, that it was hard to believe. The power of one million exploding suns, as the Professor called it, but that wasn't quite accurate.
Robert rises into the sky and doesn't stop until he has reached deep space. He looks down at the Earth and smiles lightly. His increased and incredible mental abilities, combined with his powers, allow him to see and hear so much that it might drive lesser men insane. He thinks about his life up to that point, the things he did, what he experienced, the bully who made his life at school miserable and even the woman he used to love. All of that was now unimportant. He had become more, and now literally floated above his previous problems. The only question now was what he wanted to do with his life. He could do anything and everything he wanted.
He had reacted ruthlessly to the Professor. At first, he thought about killing him, since he knew too much, but changed his mind and simply erased all the memories he had about the Golden Sentry Serum and him. He thought it was a good way to deal with the man. But Robert heard and saw everything happening and imagined just how much good he could do now that he had these powers. He wanted to try to do good, as it was something he desired to do.
.
The Sentry debuted before a world that had almost forgotten superhuman Samaritans. The last one was Captain America, but he was gone for now. The Sentry was an optimistic and socially accepted hero who stood in marked contrast to the mostly freakish nature of the other heroes. He had connections to Mister Fantastic, Iron Man, the Hulk, Spider-Man, and Professor X. He was one of the very few superheroes active during the years just before the Fantastic Four's emergence.
A lot of good could be done, and Sentry did. He created his own costume by manipulating the molecules. Sentry gained new importance when the new wave of heroes rose to prominence. But after years of doing what he did, he started to feel that the Universe and even the Multiverse were becoming chaotic. One day, after playing with his powers for a while, he discovered a way out of the Marvel Multiverse. It wasn't that he hated his life, but he was interested in seeing where it would lead him.
Robert arrived in a new reality, the Invincible Multiverse. Realising that the Earth he arrived at was, at that point, less chaotic, Robert chose a different approach. He could return to his original universe whenever he wished, but he would stay and help those who couldn't help themselves here as well. Robert created a school and a home for children of different ages, who had no one or needed someone to help them.
__________________________________
Another warning here: I'm not a native English speaker. This is a harem, even if rather small—two or a maximum of three. He will be able to return to Marvel and even go to DC whenever he pleases. It is an Overpowered MC.