When he was very little, Izuku found a strange cave that had a massive hole in the ceiling and an oddly mystical lake with a rock that was overgrown with weeds and who knew what else. His friend Bakugo had been unimpressed with the lack of treasure or anything else interesting, but Izuku had found it a place of quiet...and would treat the hidden cave as his secret hiding space.
It was only when he was twelve and having a really bad day that he would find out what the overgrown rock in the middle of the lake actually was.
Izuku stumbled into the cave, wincing at the bruised rib he had from Bakugo's quirk.
You would think the teachers would at least chastise the boy for not controlling his power properly, but no...they had to praise him for creating a blast radius strong enough to throw the quirkless kid with dreams of being a hero into a damn tree.
Any friendship he had with Bakugo died once the teachers stopped bothering to tell him off for using his quirk on the 'powerless' kid in class. The more they praised him, the worse his ego became until he was an obnoxious prick.
And puberty, Izuku knew, was only going to make that problem worse.
Now, if there was one thing Izuku knew about the small lake in the cave, it was that it was nice and cold and would likely feel really good against his bruises. At the very least it might numb the pain a bit...enough to hide it from his mother.
Izuku slipped out of his clothes and into his boxers. He didn't want to explain why his uniform was soaking wet later. The water was chilly, and he might have jumped out if not for the fact it was cold enough to soothe his poor ribs.
He soaked in the lake for at least twenty minutes, until he started to shiver. Knowing he would have to warm up a bit, and since he had some time to kill before dinner, he decided to go for a swim. He had never really been to the center of the lake, where that odd rock was.
The rock was really strange. The bottom half looked normal, but the top half...well, it warranted a closer look.
Izuku brushed off a bit of the top...and was startled to feel something like metal.
Confused, he brushed a bit more off the 'rock'...only to discover that it wasn't entirely a rock at all.
There was something else there.
Excited, Izuku would have cleaned it off, had he not noticed the time. He would have to come back tomorrow.
He barely managed to make it home in time.
The next morning...
Izuku went straight out the door and headed right to the cave. Today was a day off from school, and he hadn't bothered to hang out with Bakugo since the ass had found that he became more 'popular' whenever he used his quirk on Izuku.
Ever since they started middle school, Bakugo had discovered his 'popularity' only increased by using his former friend as a punching bag. Especially if he used his quirk.
Izuku swam towards the center of the lake. He had barely made to the cave in time, a nasty storm was about to hit today, which meant he would have to spend a few hours inside anyway.
Using his hands, he managed to slowly but surely uncover the secret in the rock.
It wasn't a rock at all...not entirely anyway. The growth had hidden something incredible...a mysterious metal weapon that almost looked like a hammer, but was far too bulky compared to the ones he was used to.
Izuku reached for the handle of the weapon. His hand grasped the smooth metal/wood combination, and he felt something weird from it. It almost felt like it was testing him for something.
He carefully began to pick up the hammer. It had taken him an hour to clean off the worst of the muck on it, and it looked really heavy.
Strangely, the hammer was surprisingly light in his hand. It had a bit of weight to it, but not to the extent he expected.
Unseen, the storm clouds began to gather in force above the cave. Lightning rolled across the horizon, gathering strength. Thunder peeled across the town.
Izuku lifted the hammer completely from the rock.
The sky cracked open as a massive bolt of thunder struck the cave squarely in the opening, hitting Izuku directly. It was utterly terrifying.
Izuku thought there would be pain...after all, most people are lucky to survive a normal thunderbolt. This one was far bigger than any he had seen his entire life.
Instead of pain, however, there was a strange surge of what could only be power flowing through his veins. His bruises and the other odd injuries he usually got from Bakugo healed over in a matter of seconds, and the power of lightning seemed to make him even stronger than before. Like he was the lightning.
When it was all over, Izuku nearly dropped the hammer. He was panting from shock and exertion.
He would honestly say he had no idea how he made it home that day. His mother was worried sick, and once he ate dinner he went straight to sleep.
Over the next few days, nothing really special happened. Bakugo was still an ass, but Izuku didn't really give him much opportunity to harass him.
Then it happened. After a particularly bad day for him, in which a teacher actually bitched him out for using his quirk on another student...who wasn't Izuku naturally, but he had come to 'accept' the hypocrisy of the teaching staff when it came to Bakugo... the blond went looking for the one student he could more or less bully as much as he wanted to establish his dominance again.
Izuku found himself cornered by Bakugo and his idiotic cronies. He knew it was going to suck, but he wouldn't give the bastard the satisfaction of seeing him cry.
It took Izuku five long minutes to realize Bakugo's punches didn't hurt as much as it normally did. In fact, he barely felt them and he knew all too well Bakugo didn't bother holding back his punches when he was in a foul mood.
Years of pent up frustration and anger over the fact the teachers would ignore almost anything done to him by Bakugo or his cronies because he was 'quirkless' and his dream was 'pointless' because he didn't have a special power fueled what happened next.
He was sick of being picked on. He was tired of everyone telling him that his dream was hopeless because he wasn't born with some fancy ability. More importantly he wanted to let Bakugo know he didn't appreciate being used as a damn punching bag simply because he was a convenient victim for the blond.
He balled up his fist, and before he could really stop himself, punched Bakugo square in the nose. The feeling was incredibly satisfying.
However what he expected to happen and what actually did were so far off that it was hard to explain.
He fully expected Bakugo to at worst get a bloody nose. Sure, it would mean a worse beating than normal, but he was sick of this.
He did not expect the blond to be sent flying into the wall and be knocked out conscious.
Seeing their ringleader knocked out cold by their punching bag, the other bullies stared dumbly at the scene. Then they heard a sound, and like the sheep they were, scattered.
They only followed Bakugo because he was the 'strongest' and it meant they could bully others to make themselves feel more powerful. They never expected their usual victim to fight back, or to have the strength to take out the explosive blond.
Izuku looked at his fist. Then at Bakugo. Then at his fist again.
Disbelief filled his features, before common sense and long experience kicked in and had him vacating the area.
The hallway might not be well traveled, but he sure as hell didn't want to be seen by anyone of authority with Bakugo out like that. For one thing they'd blame him and never really give a damn about the fact Bakugo had cornered him there to beat the shit out of him. For another he didn't want to explain how he had knocked Bakugo out with a single hit.
He needed time to think, and after that thunderstorm he wasn't inclined to go to his usual spot.
He headed straight home, since the day was already over and he didn't want anyone to stop him.
His mother was out with her friends and wouldn't be back until dinner.
Izuku went and pulled out the strange hammer he had found. Apparently it was called a 'warhammer', which was the closest thing he could find matching it's description.
He finished his limited homework in record time. He needed the distraction.
Then he turned on his computer. He needed information, and his best chance to find what to look for was on the internet. Rather than go to his usual hero sites, he typed in his favorite search engine.
He typed the words 'war hammer' and 'lightning', as he vividly remembered that massive thunderbolt and how he managed to survive it.
The first thing that popped up was references to a game called "Warhammer". He ignored it and tried a different tactic. It took him three more tries to get the right words to find something useful, and that was mostly due to old legends about a sword in a rock.
"Mjolnir, the mythical weapon of the Norse pantheon belonging to Thor, the god of thunder. Mjolnir is one of the most iconic weapons in the Norse pantheon and the most famous mythological hammer of all time. It is known to channel lightning and create storms. Legend states that only those 'worthy' of wielding it's might are allowed to carry it, though Thor is the only known owner to date," Izuku read.
There were several 'possible' pictures of Mjolnir, but the limited description fit the hammer he had found well enough. However the only way to know for sure if he had found the legendary hammer would be if he could summon lightning with it.
Izuku went to a different secluded spot. He had the hammer in his backpack, and it was still a lot lighter than he expected.
Making sure no one was around, Izuku took it out. It fit almost naturally in his grip.
Then he realized something important.
He had no idea how he was supposed to summon lightning of all things!
Almost as if the hammer could sense his thoughts (it could, to an extent), lightning began to crackle along the head and on his hands. The second he registered this important fact, he yelped loudly before accidentally throwing it at a nearby tree, which blew up from the force.
Izuku stared at the destroyed tree, then at the hammer in his hand. Electricity still crackled along the metal, but it merely felt 'tingly' rather than painful.
"No way..." he said in shock.
He had stumbled across an honest-to-kami mythical weapon! More to the point he was able to use a small part of it's abilities! This was... this was beyond words!
Izuku's usual habits of over-doing things lead him to extensive experimenting with his new weapon. Finally, a chance to be an actual hero and to help protect others!
However, there was one small issue. Namely that the hammer was far too noticeable and it wouldn't take long before an adult tried to confiscate it. If they could anyway...he had discovered by accident when his mother attempted to lift his bag...which had Mjolnir inside...that only he could lift the hammer as it was 'too heavy' for her.
It took him all of a month to figure out the most basic of basic tricks...and a few others that would drive people crazy but weren't actually illegal.
Case in point, when he accidentally learned how to siphon off power from electronics. Took him hours to figure out it was his fault his laptop couldn't hold a charge while he was practicing. It wasn't much of a power boost, but as a tactic to drive others to frustration, it was rather effective.
He could think of several people who would be driven up the wall because their precious cell phones suddenly died.
To that end, Izuku started quietly siphoning power every time he left the house. It was a bit tricky, but eventually he figured out how to do it without having to concentrate so much.
(It would lead to a rather amusing situation later, but that was another story.)
The first indication it was working was the outraged cry from one girl in class who was constantly texting on her phone.
Needless to say it was confiscated by the teachers almost immediately, but that lead to an avalanche of students taking out their phones only to discover their batteries were completely dead.
The only person who didn't lose their phone that day was Izuku, and that was because he didn't want to drain his own battery as well.
It was surprisingly easy to move from draining electronics in a confined area to leeching power directly from the wall sockets. Sure, it made the electricity bill skyrocket to rather appalling levels, but so long as he never did it in his own home he never bothered to think too hard about it.
It wasn't like anyone could trace it back to him, as everyone knew he was "quirkless". And if he did suddenly gain one, most would expect him to crow it to the roof and show it off like everyone else did in class. They'd never believe he'd keep his silence.
Izuku was rather curious about a new villain the heroes were having trouble finding. They were calling him "Blackout" because whenever he showed up, all the electronics in a certain area were knocked out...including security cameras. It took the power companies and other workers hours to get things functioning again.
The problem was no one had any idea what the villain looked like, just what his quirk was. Trying to find an energy vampire was proving rather difficult as they had yet to make any real attempts at criminal activity.
It would only be much, much later that Izuku made the connection between "Blackout" and his habit of siphoning off electricity from the surrounding area. As it was, he was incredibly mortified learning he had his own villain name despite not actually DOING anything.