Side effects and Training
"So you're telling me that in the seven thousand years you've known each other you've never thought of building weapons to channel and strengthen each other's powers?" Izuku asked amusedly as Phastos and the others fidgeted in embarrassment.
It was a few weeks after Izuku first met the Eternals, he found himself coming back to the Domo every day to talk with them, to speak with people who don't shun him for not being special. In fact, when he told them what became of the world after the rise of quirks they were disappointed in humanity.
He found himself getting comfortable with them very quickly, faster than he's ever gotten with anyone else. He guessed it was because he had the Celestial Orb in him, which they still couldn't figure out how it affected him. Other than being stronger and faster and having more stamina than he had before.
"Well we never had to, our powers were already enough for whatever threat we had to face." Kingo tried explaining as Izuku started cackling.
"No he's right, not all of us have offensive powers. If you and Phastos had banded together to make a gun or something that shoots out stored cosmic energy we could have helped fight Deviants too instead of just guarding the civilians." Druig stated, he was a bit bitter about always being on the sidelines getting the humans to safety and never being able to fight because his power didn't work on Deviants.
The silence that greeted his words only made the teen laugh harder until he was rolling on the floor in hilarity.
It was a month after he found the Eternals that he found out what the Orb did to him. He was doing his usual routine of cleaning up the beach, which was going a lot faster than anticipated with his newfound strength and all. He was dragging along a fridge in the sand when he plopped to the ground next to it in exhaustion. He desperately wished the fridge could be lighter, like feathers, that would be nice. When he touched the fridge to help himself get up he fell down again as the fridge melted into a swarm of feathers. He stared at his hand in confusion and then excitement before hauling ass to the Domo to tell the others of his discovery.
Once there the immortals were awed by his tale and Ajak asked Phastos to run a diagnostic scan on Izuku to see what could have caused the sudden manifestation.
Once complete, the scan showed that the teen's body was full of cosmic energy, not as much as an Eternal, but enough that it would have turned any normal human to little more than dust. Phastos speculated that since the Celestial Orb was already an object of cosmic energy, and that they added their own cosmic energies to it, that it was possible that Izuku now had access to their powers.
His hypothesis turned out correct when the greenette suddenly startled and stabbed an energy sword behind him as he turned around. Sprite dodged backwards from the stab and fell on her ass.
They decided that since he wanted to become a hero and that now he had their powers it was their duty to help him learn how to use them. He was already behind the others who awakened their quirks at four so the training Thena proposed was brutal and efficient.
Time training with Sersi was fun. She taught him the best type of materials to transmute things into in different situations. She basically used transmutation to change the atoms in whatever she was touching, when asked if she could transmute air she plucked a rose out of nothing and handed it to him. Izuku wrote every idea he had for ways in which to use her power and ways that she herself didn't think worked.
"If you can change atoms then why can't you change the object's shape?"
"I don't know," she started off hesitantly, not wanting what happened to Kingo a few weeks prior to happen to her, poor man was laughed out of the room. "We came out of the Domo with innate knowledge of how to use our powers. I guess I've simply never thought there was more that I could learn seeing as Eternals are incapable of evolution."
"Well that's bull," he snorted, "let's try it out."
Izuku ran to the practice area and kneeled before the transmuted sand, he easily turned it into hard packed earth and tried to change it. He focused on the shape of the earth and imagined it moving, the atoms that made it changing positions and taking form under his will. It took a few minutes and he was sweating by the end of it but in the end he held a rudimentary earthen mug in his hands. She gasped when she saw it and gently cradled it in her hands when he handed it to her. Druig and Makkari interrupted their conversation when they heard her and moved closer. The sorceress showed them, Druig seemed to lose interest when he saw what it was.
"This is what brought forth that gasp?" he asked sardonically. Makkari slapped him on the arm for it.
"It is when he made it using my power and solid dirt." That got Druig's attention.
"I thought you could only change the matter in which it is made?" Makkari signed.
"That's what I thought too. But Izuku changed the form of it, he touched the earth and turned it into that."
"If that's true then that opens up so many possibilities..." Druig said fascinated by the figure in his hands.
"He has a full notebook of ideas for our powers. I bet this isn't even the most impressive idea he has." Sersi boasted.
Makkari suddenly disappeared only to catch Izuku as he lost consciousness.
"I guess doing that is a lot harder than simple transmutation." Druig mused as they all stared at the teen in worry.
"Yeah I guess so, can you put him in the my room, I'm the reason he's like this now its the least i could do." Sersi told Makkari. She nodded before zooming away to the sorceress' room.
"I wonder what other ideas the lad has." the Irishman pondered.
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"So you're saying the reason I blacked out is because I used too much cosmic energy?
"Yes, think of it like a muscle, the more you use it the easier it'll be and the more you'll be able to use it without hurting yourself. It's like running a marathon without exercising first. You just need to allow your body to recuperate and get used to the new energy it holds, as well as practice basic skills more so you can then use more advanced abilities like the one that landed you here without harming yourself. Your body becomes more and more saturated with cosmic power with each passing day, soon you'll be able to do what you did today without breaking a sweat. Why do you think we haven't taught you how to use Kingo's energy blasts or Gilgamesh's gauntlets? Your arms would be ripped apart without preparation. You need to build up more cosmic energy." Ajak explained.
"Got it." Izuku said, blanching at the thought of what could happen to his arms without the proper training and preparation.
The Prime Eternal just ruffled his hair and laughed softly as he started drifting back to sleep.
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His training since that day was upped considerably. Thena said "If you can use advanced transmutation better than someone who's had that power for several millennia then you can go one more round." Before proceeding to kick his ass again and again as Gil laughed in the corner with Kingo and a bag of popcorn.
The cosmic energy flowing through his body increased his physical abilities a lot quicker than a normal human's would, that combined with Ajak's healing made Thena and Gil train him from sun up to sun down most days.
Sprite and he usually had illusion competitions where the Eternal would correct him and add details. "Nothing is that smooth, everything has some imperfections." They kept repeating until he got it right. "Don't forget the small details, whose are what make it seem real." Animals and monsters were harder because he had to recreate that predatorial grace that most carried themselves with. Sprite just told him to use Thena as an example.
He asked if they had tried to trap someone in an illusion before, an illusion that only their target could see. They said no, their powers were mostly used to entertain crowds or draw attention towards or away from something. But they were capable of transmitting memories, they'd done it for Bu-Sik Kim in 12th century Korea (read the Webtoon comic to know) so he could complete his scroll. They were able to manipulate dreams pretty well and memories to some extent via physical contact.
The day Izuku first got permission to try out Gilgamesh's power he broke his arm in three different places. Luckily Ajak could heal it perfectly. He tried again but dialed down the amount of cosmic energy channeled to his arms and found that they didn't shatter on impact. He was still sore though, he'd have to practise more so that it went away.
While he could manifest cosmic weapons, he couldn't wield them as well as Thena did, for obvious reasons. She taught as best she could and he sucked it up like a sponge, which isn't that hard when he's a genius who's finally able to go all out with his questions and has a teacher who's actually interested in teaching him instead of belittling him. She taught him much and helped him vent his pent up rage in the arena against transmuted dummies. She wasn't one for words but she was a great help. Kingo walked in on them discussing the best way to exact revenge and/or gut a man in the most painful way possible several times and learned to just walk away ever since the blond suggested using him as an example.
Inventing with Phastos was always fascinating, being able to put the countless ideas swimming around in his head out and bounce them on someone who listened was amazing. They'd successfully built a hero costume and several gadgets and support items he could use for almost any situation. More than once Ajak interrupted their inventing sprees to feed the teen because "growing boys need their protein" while chastising the inventor for forgetting to feed him.
Kingo taught him to shoot his energy blasts and gauge their power so he doesn't blow a hole through whatever or whoever he's shooting. They made it a game with Sprite to see how many he could hit at multiple distances, like those games where you had to shoot the enemies but not the civilians. They did the same but every time he shot a civilian kingo would zap him with a low level beam until they started their own zapping war.
Druig taught him more about diplomacy and manipulation than anything. How people work, what makes them tick and what buttons to press to get the reaction he wants. Because his powers don't work on other Eternals Izuku had to learn how to do it stealthily. He stood in a crowd wearing an atrocious outfit and used some light mental manipulation to make people ignore him. It worked like a charm.
With Makkari it was all reflexes and speed. She would throw tennis balls at him and he had to dodge or catch them, but he had been dodging Bakugou and his lackeys since he was four so it quickly became too easy. So she moved on to paintball guns, let's just say he quickly got better.
Ajak, while not teaching him much about fighting, was very motherly and took care of much better than his real mother ever did. He's sure that if she could leave the Domo she would give Inko a piece of her mind in the form of her fist while Gil and Kingo cheer her on from the sidelines. She helped him in dealing with his emotions and accepting that some people just weren't worth forgiving. That people who burn and mock and kick and belittle him aren't his friends. She cried the first time he called Kacchan Bakugou. She hugged him tight and told him she was proud of him and his progress.
Izuku found a family in the imprints of nine immortal cosmic beings and he wouldn't have it any other way.