Disclaimer: I don't own My Hero Academy or Inuyasha

This is set in the if Inuyasha never met Kagome and was unsealed situation. Please ignore all plot holes and stuff, I was working on the fly for fun. And no, no romance.

He had been sealed, by Kikyo. By a sealing arrow against a sacred tree.

Disbelief colored his eyes but he couldn't fight the effects and drowned in the darkness. The Shikon no Tama rolled from his fingertips into waiting hands of the Priestess.

What happened after that was a long battle, one he never participated in because he was sealed, for as long as the seal wills.

—

Sesshomaru looked up at the tree that sealed his half-brother with cold eyes. Red shone brightly against the darker bark and white so much lighter than his silver swayed a bit in the wind. It has been fifty years since he had been sealed, that foolish brother of his.

When he actually needed him, he couldn't be counted on and was sealed by a mere human. Sesshomaru gave one last lingering glance and turned away, leaving Inuyasha to his seal for who knows how long.

But he will be back to check on him time and time again, perhaps the seal would be undone sometime soon.

He would not be satisfied for Inuyasha to perish just like this.

However unworthy he was, he was still of Inu Daiyokai blood.

—

After he saw Inuyasha, it was like it was the start of everything.

A human girl so distastefully similar yet dissimilar from the Priestess that sealed Inuyasha appeared along with the Shikon no Tama.

After that were so many irritating events and people. But he mainly watched from the sidelines until a foolish spider tried to drag him in. He held no interest in false power, he was fully confident in his own.

He did not really pay attention to what happened to the girl and her group, nor of the Shikon that so many lusted for. He merely continued his wandering and search.

He never did find Tessaiga, he was quite certain it was on his brother. But no matter, he had gotten another sword crafted, at least that one could kill, unlike a certain Tenseiga.

—

The next time Sesshomaru heard about the Shikon no Tama again, it was of its destruction. He paid little attention to it and went to see his foolish brother. Although it was a bit early, he felt an urge to do so. Tenseiga was also making some oddly persistent sounds.

It only became more demanding after he was finally acknowledged by the blade. He was getting soft, saving a human girl.

But he went, only for his eyebrows to rise a bit in surprise.

Purple marks lined Inuyasha's face… much like his own, except it was only a pair. His demon scent also became stronger…

Mildly interested and curious about the change, he went to find someone who could provide an explanation. He never heard of a half that could turn… into a full demon.

If Inuyasha could turn into a full demon eventually, even he would not be as foolish as to fight for some Shikon no Tama to turn him into one.

He sighed, lately he felt less of the hatred from before. Now it was just more… indifference.

—

Inuyasha didn't know how long he had been sealed, just that he was still sealed. At first, it was darkness, never-ending darkness he was never conscious of and would likely never come out of.

But at a certain period of time, he felt his conscious stirring… from pain. Something was burning from within him, slowly killing his mind as he felt bits and pieces of himself slip away.

Once in his misery, he scented a rather old and familiar scent.

Ah, it was Sesshomaru… was he here to finish the job? To kill him?

He honestly didn't know which was better now, to die by those poison claws of his brother, or to slowly lose himself to the tearing haze of heat.

He heard a soft sigh, then a rustle of clothes and grass as footsteps gradually became softer.

So he wasn't even worth killing in his state.

Bah, he wasn't so weak as to lose to this, or want his brother to kill him. He lived for so long, he would definitely survive this and break out of this seal.

But damn Kikyo could seal demons.

He ignored the slight pain in his heart at the thought of her and sunk back down in the haze of pain and darkness.

—

He didn't know how long he had been in this constant feeling of being burned from the inside out. It continued for so long he had became numb to it and put more focus on the world outside around him.

A rustle of grass and an aching familiar scent.

Ah, he came by again…

Funny how one day he would actually look forward to Sesshomaru visiting him, but in his haze and sealed state, there was nothing else to do.

He felt a soft pat on his head, a sigh then a swish of clothes as the familiar scent left him.

Always the same, the same coldness and indifference… but it has turned gentler with time… it would have been nice if he was like this from the start, perhaps he wouldn't have to grow up all alone as a child.

Hm? He also seemed to be turning softer… it was just the boredom.

—

Sesshomaru visited again for who knows how many times and stared at Inuyasha's slowly turning form. Bokuseno, that old tree yokai had said it was possible for a half demon to be taken over by their demon blood and turn pure, but at the cost of their sanity and the destruction of their body.

It wasn't a true transformation, just a loss of oneself into destruction until death.

And it only happened when the half is beaten so close to death that their blood takes over to destroy everything around them until they themselves were destroyed.

So even sealed he was slowly dying… or close enough something triggered his demon blood to take over. Perhaps this brother of his would never get the chance to come free before his body was destroyed.

What a pity, he was actually starting to feel… like he wouldn't mind this brother of his anymore. His mother had fallen to some other demon, so now he and Inuyasha were the last of the Inu Daiyokai.

Time was changing so slow, yet so fast. The numbers of yokai were slowly diminishing while humans increased.

Perhaps soon, he would no longer stand on top any longer.

Humans… were truly more progressive than the never changing yokai.

—

When the haze was about to tear away the last of his sanity, Inuyasha found himself somewhere.

A large dog-like skeleton was before him in full armor.

He looked up at it in fascination and started to slowly walk around. He looked down at his hands and they looked a bit hazy.

Perhaps this was the afterlife? So he was finally dead? Well, perhaps it was better that he was dead now then stay seal any longer when death seems to still be his end.

He wandered around until he noticed a hilt. He didn't know why, but he humored himself into picking it up.

He swung it around, it was quite a shabby sword, but it wasn't like he had anything better to do. He continued to play around with it until he noticed something off was happening. The sword was starting to vibrate–

Everything collapsed around him.

He was back to being sealed.

—

Tenseiga vibrated intensely, arousing Sesshomaru attention immediately.

It was rare for this sword of his to have such an intense reaction, and he was on his way to visit Inuyasha.

Perhaps something happened to him?

He quickened his pace and was soon in front of the large tree, his sword vibrating and shining even more intensely.

He observed Inuyasha and started to see the imps appear… so he was starting to die.

Then, another aura came from Inuyasha, slowly taking the form of a sword.

He widen his eyes. Although it looked shabby, only one other sword would have such a resonance with his.

"Tessaiga?"

Tenseiga urged him, and he looked down at the sword hanging at his waist. He then unsheathes it, and slashed down at Inuyasha.

—

Ever since that day, it was like his body finally stabilized. Whatever that was burning him no longer burned through him, but somehow his body did not feel entirely his own.

His hearing was sharper, his smell was sharper. Something felt constrained in his body, and for the first time, he felt the seal give way a little more. He pushed harder at it, but it still tired him and he quickly fell under.

At least he had a way out now, he just had to fight it.

—

Sesshomaru waited, and waited. He continued to wait, even as the scenes around them changed, the very society changed along with the very air and water.

Thankfully he had acted ahead of time and bought the entire place where Inuyasha resided and made it private property. The current estate prices were much higher than before, and forestry was becoming more and more scarce. It was getting harder for the remaining yokai to find places to hide.

Those that could transform did so and blended into society. Others that could not fled deeper into the depths of the environments. He looked relatively human, but he too, mainly left it to others that could transform and stayed in his land. Jaken could take care of those underlings for him. That little imp stayed with him for so long, it was simply natural.

He looked up at the still sealed yokai and sighed. He had been seeing movements occasionally, but nothing concrete. Just some twitches here and there.

He started his more recent habit of visiting Inuyasha: talking.

Talking about the recent events, how society has changed, etc. Although he was still aloof and indifferent, he was not as bad as before.

Time truly mellows all.

—

Inuyasha doesn't know how long he had worked at breaking the seal.

Damn it, Kikyo made it way too strong! From what Sesshomaru has been saying, it's been literal hundreds of years since he has been sealed!

He silently cheered when he could make small twitches which were immediately caught by Sesshomaru, who then decided to check on him even more than before.

This brother of him was truly patient, Inuyasha had to give that to him. If it were him, he would had probably raged at him already.

That year, he felt that he was the closest he had ever been to breaking through. It was a good time to break through too, since he heard that brother of his saying how humans have started to accept the supernatural–quirks.

Yokai could now pass off their powers or appearance as quirks and be fully accepted by society. So even if he were to go out with his dog ears, he would be fine. Sesshomaru himself had also started to make more trips outside, though his noble appearance and cold temperament still turned heads.

Not to mention his ancient-style clothing and armor. He still prefers his old robes compared to the recent modern fashion, if he could forgo following the norms of society, he would.

—

"Inuyasha, how much longer are you going to make me wait?" Sesshomaru forlornly stared at Inuyasha, forever dressed in his bright red fire-rat robe. The robe was a good one, still tough like before though a bit dirtied. Being sealed on a tree for so long would do that to anything.

"Coming… out!" Inuyasha finally made one last effort and broke through, much to the pleasant surprise of Sesshomaru.

"It's been a long time, Inuyasha." His words held a faint chuckle as the other grunted and fell from the tree rather groggily, the old arrow finally vanishing into light.

"Uh… hmph." Inuyasha stared at him a bit blankly, then turned away and huffed a bit, appearing to be a bit embarrassed and awkward.

"Come, I will have Jaken draw you a bath. It's been a very long time Inuyasha."

"Eh, that old imp is still around? You never bring him around to see me so I thought he finally ended up dead somewhere."

Yes, still the same blunt Inuyasha.

"How rude, I am perfectly well and alive!" A squeaky voice came through.

"Jaken."

"Yes Lord Sesshomaru!"

"Bath."

"Yes, of course!"

"Tch, still the same sucker."

It was nice to have him back.

—

"So, you're telling me I'm not a half anymore? I'm a full?" Inuyasha spoke through his mouthful of food, his legs crossed and his bowl up in the air. He was the very picture of crude.

"A half would not have been able to survive as long as you have. Your sealed state caused your demon blood to fight. You would have ended up dead." Though if things went the way it did without his Tenseiga, this idiot brother of his would still end up dead.

"Huh, that explains all the pain I felt before and my sharper senses." Inuyasha did not appear to care as much as Sesshomaru thought he would have at the news. After all, his desire of being a full demon was what caused him to become sealed.

But he also couldn't care less about the subject. "You were conscious the entire time?"

"Nope." A loud slurp that caused him to internally wince. Manners had to be taught soon. "After a while I started to gain consciousness, though the pain sometimes takes me under again. It was a fucking pain! One time I thought I was dead. Ended up at some place and there was a huge skeleton and a sword. It was so shabby though."

Ah, he had so much to explain. He will just explain their fathers part while Jaken can take care of the rest. He was not one for too many words.

He picked up his tea and sipped it quietly as Inuyasha continued to blab through his food, the previous awkwardness completely gone.

—

"Huh, heroes?" Inuyasha's face was one of pure confusion. "What's that?"

"A profession nowadays where "good" fights "bad". They call the bad ones villains."

"Are you fucking kidding me?"

"Lord Sesshomaru! All Might is at the entrance waiting for you Milord!" Jaken's squeaky voice came through.

"The fuck? All Might? What kind of name is that, hahahaa!"

Sesshomaru sighed. He didn't want to deal with it either.

—

"Hey, so we can't use our 'quirks' and stuff unless it's self-defense?"

"Yes."

"Tch, I wanted to fight some of these 'villains'. Entertainment is good and all, but I want to stretch my muscles!"

"The only way to legally fight Villains is to become a hero, you stupid half!" Jaken reprimanded him.

"I'm a full-blooded demon now." Inuyasha picked up the imp by the neck and threw him aside. "And there is no way I am becoming some stupid hero."

"Doesn't matter if you're full blood or not! You'll forever be that dirty half to me!" Jaken squawked indignantly and went to Sesshomaru who ignored all the racket behind him while dealing with some email.

"Sesshomaru~ I'm bored~" Inuyasha rolled around on the floor and the elder one finally sighed.

"I can probably get you into U.A High to fight some hero trainees."

"Tch, weakings."

"You are weak as well."

"Why you-!" Inuyasha lunged at him.

Sesshomaru won cleanly of course.

—

"So, today is a special class. You guys get to fight someone." Aizawa drawled out tiredly while the class cheered.

They quickly met… the teen? He looked older than them, but not in his twenties yet. His eyes were a molten gold, jagged purple stripes lined his cheeks and a pair of dog(?) ears were perked on top of his head. He wore a red robe and was barefooted.

Behind him, they could see someone that looked similar to him, but that man carried a far more noble and elegant appearance than the rough one in red. He didn't have dog ears, but there was a rather large fluffy thing over his shoulder.

They were clearly related.

"So, you all are the twerps I'm supposed to beat down."

"Huuuhhhhh?" The first one to take the bait took it hard.

"You can't kill them." The one behind intercepted.

"I'll hold back, they're just twerps. I can do them in with just one hand."

"I'll fucking kill you mutt!"

—

The fight was a complete loss and disaster. They learned pretty quickly that those claws weren't for sure. The teen–Inuyasha was his name–made a complete joke out of them. He was so quick on his feet, yet someone that could take a hit and hit back hard.

The worst part to come was when he got so excited he transformed into a giant dog.

"Holy mother of all pizza." Someone gasped out and people had to agree.

Though before the teen-turned-giant-dog could commit mass destruction on them, the other guy-his brother?-finally sighed and stood up from where he was sitting and watching.

"That's enough, Inuyasha."

And Holy Shit, he also turned into a fucking giant dog even bigger than Inuyasha and beat him down, making him transform back."

"We need to work on your control." The elder sighed.

"Damn you bastard." the younger one was flat in the ground, twitching in pain.

The hero class was the one that wanted to complain. No one wants to fight some fucking mythical looking creatures.

Just wanted some brotherly relationship... I dunno, I think I went brain dead somewhere