You may have heard this somewhere: "we think time is a living thing."
Prologue
At the beginning of the Universe, physical qualities were determined by the power of the Constants (think giant blobs that coexisted together in super symmetry).
Well they had a disagreement, and Time broke free first. The others ganged up on Gravity and weakened it substantially (you can read the timeline of the cosmos on that wiki thing if you want).
Time was really excited at first and pushed out into the nothingness as fast as it could, but you know after a billion years, Time settled down and just stayed in the formation of a galaxy where Time ended up. Planets were forming by this time.
Earth -1
On Earth , life progressed from the bacteria to animals with only a couple hiccups (read mass extinction events) until we get the apes. Similar things were happening across the galaxy. There wasn't anything exciting though until three Monolithic stone tablets reached Earth.
Seeing how, most of the earth's surface was covered with water, only one made it to land. And an Ape had been the first animal to touch it.
That Ape was given a consciousness and whoever sent it also gave the Ape an accelerated learning aptitude. So the ape started making things like tools to get more ants. Unfortunately for him though, a highly-radioactive meteor had exploded in the air one night, close to his cave. When he woke up, he already had gotten bit by a baby spider (a genetically modified spider that had hatched prematurely early, which made him itchy and frustrated.
He soon learned that whenever he got really frustrated and/or angsty he transformed into a giant green monkey that wreaked havoc on local wildlife. He also had amazing reflexes and could sense danger before it happened. Which allowed him to destroy most of the other genetically modified spiders in his rampage.
He couldn't control his primal destructive tendency in this state, but he would turn back into a his intelligent Ape form after at most a couple days.
Understanding that he had power and that if he wasn't careful, he would hurt and destroy his fellow animals. He decided he had a responsibility to control his powers. So his exponentially adaptive brain started experimenting with foods, minerals, chemicals he collected with his increasing arsenal of technology (he had gotten to the lightbulb era by this time). He eventually tried various medicines that kept altering his DNA ending up with a particular gene. None of the medicines worked for long, but he had made arm band and outfitted the cartridges with stronger and stronger sedatives in an attempt to calm his inner rage. He began shedding his hair, until he didn't have any.
So he turned to his creator. He didn't really think too deeply about it, but for some reason he believed that he was created for a reason. So he fasted and meditated. He saw images of other animals and of other apes. He his mind's eye to draw symbols and patterns into the ground. Until finally an iron spear with an engraving appeared before him.
His interpretation was that he would show the other Apes how to hunt (they never really got the hang of it until a some generations later) and how to cook meat. However, seeing how this was futile. He ended up just leaving the ant scooping tool with the ones he met.
One day after years of travel, he got the vision of a tall mountain (this wasn't a vision though just a dream. everyone can mistake dreams for having deeper meaning) so he went to scale the tallest one he could find. And he got pretty high in his rage form, until he dropped down because of oxygen deprivation, became a regular bald humanoid and had the misfortune of being covered in an avalanche and freezing.
Fortunately though, after going through so much mutations and acquiring celestial power, his life force was preserved and his cells just went dormant.
That was until a little after 1910 AD. Some climbers recovered his body and shipped it to a facility in europe with some visiting American scientists who were at the top of their fields in anthropology for an autopsy and coincidentally the fledgling genetics field. They took a sample from the Ape which looked pretty much like a human, except completely hairless. But by that time the cells had started to regain energy, and the act of taking a sample triggered the danger (read spidey) sense.
Waking up, the Ape might have been able to understand what had happened, but the mutated chromosome had given him telepathic ability, and all the voices he heard frustrated him beginning the transformation into the green ape. The guard immediately reacted and started shoot the ape out of fear of the unknown. The ape managed to take a couple of shots and dodge some others, but he was still weak.
In the moment before he was shot through the heart (among other vital organs), the ape saw a vision of Tony Stark defeating a world destroying white and purple alien with a tail preparing to destroy the earth. And the ape knew and figured the significance and was happy.
The guards and facility were in a highly superstitious part of europe and decided to exorcise and burn the corpse much to the American's pleas to have the specimen. However, they realized that they still had the sample which they later used to splice it's DNA into humans to replicate the power they saw. The first 3 test pools didn't show any results during their life, so the organization shut the program down. The initial sample had also been almost used up and the remaining was beginning to decay.
However, the progeny developed the powers that we've seen before. Some created realms, others highly sophisticated AI and exoskelations, generally superior reflexes and strength, telepathy, healing factors, energyemission for starters, aptitude at Magic for starters.
Eventually, you're going to get a person and/or machine and/or relic that can time travel.
Decades pass, aliens get involved, the past is revised, causality starts getting corrupted.
Epilogue:
Remember Time. Well it's living. and after timetraveling becomes regular, Time is having a problem preserving causality and just keeping track of all the mess. Eventually, Time can't handle it and begins the process of a Universe's Big Crunch.
Of course we have Omega Level superheroes. Some that manage to try to fix the universe which further results in a Vacuum metastability event (read that wiki thing).
But in that moment (or rather in the moment before the moment- powers. figure.) there's a last ditch attempt to take advantage of the breakdown of physical laws and causality by all the remaining heroes and some villains which results in the
Marvel Multiverse
we all have a love/hate relationship with.
FIN.
