Toshinori Yagi was a busy man back in the silver age. Known to the masses as All Might, the indomitable number one hero that could save anyone from anything. Compared to him, no other hero was needed for anything but for the fact that he couldn't be everywhere at once, something that infuriated the number two hero to no end.
Endeavor, Todoroki Enji, was a man generally disliked by the public. Was he an adequate hero, stronger and more capable than everybody else bar All Might? Yes. Was he an irritable asshole who pushed away everyone around him with his constant dislike of his superior? Silver Age? The entire era was out to remind him that he was the silver medallist in this contest that, unbeknownst to him, had only one serious competitor: himself.
Yet, his ambitions drove him further, lower. Eventually, he realised that he himself would die looking at the back of All Might. No matter how he struggled, his genetics just wouldn't allow for him to become stronger than the strongest. His quirk was just too uniform, his attitude iron-clad. And so, he turned to the next generation.
It took a few tries, he mused. His first two sons were nothing like what he was looking for. He wanted a child born with a versatile and powerful quirk that could shut down that stupid power All Might had been lucky enough to be born with. Was the world better off with such a man doing glorified community service? Not his problem. He just wanted the number one spot, and if he wasn't getting it, his family was.
Finally, after years of something he'd rather not think about, his wife bore him Todoroki Shouto. As a child, he displayed all the advantages Enji had wished he would. A powerful quirk, taking the best of his father and mothers. The ability to use both to their fullest potential.
Unfortunately, years of being nothing to her husband but a facility to pump out a suitable heir had done some horrible damage to her. Knowing that her husband didn't even care to know her name despite all her attempts to coax some kind of real warmth out of him had drained her of her ability to think clearly, and she spent her days unfit to raise children.
And so, Endeavor took to working on his greatest project. There were some speedbumps. The boy didn't quite take to Enji as he would have liked, preferring instead the company of his insane mother. Try as he might, Enji could do nothing to sway the boys loyalty, so instead he took what he wanted anyway. He detached Shouto from his family and saddled him with intense day-by-day training, teaching him how to maximise the effectiveness of his dual quirks.
Once, just once, Yagi made a visit. It had been strictly business, a vain attempt to make Endeavor at least consider his public image for once. He had a wife and children, he could at least empathise with the people he'd sworn to protect. He noticed Shouto out of the corner of his eye, barely out of his Toddler stage and standing just around the corner, eyes wide. So this was the man Endeavor hated so much. With his incredible presence, it was hard not to imagine him as the worlds strongest. But what made Shouto the most interested was his smile. Endeavor never smiled, and his mothers were as cold as her quirk. But this mans smile was proud, warm and unfailing. Shouto knew that All Might loved being a protector, and spent every second doing everything he could to improve the living standard of the people. Not for approval ratings, or to be the number one, but just because it was what he wanted to do.
That was when All Might fully directed his attention to the young boy, eyebrows raising. "Enji! I heard nothing of you having another child. The Todoroki household gets bigger by the year!" He slipped off of the stool he'd been crouched on, the groan of metal reasserting itself implying that it had been worse off for him to have sat down in the first place. "Greetings, little one! What's your name?"
The conversation would probably have lead to Enji being hospitalised, and realising this, he cut it short by shooing the child off, telling him to finish nonexistant chores. The conversation turned back to the adults, and Shouto didn't hear from him again for many years.
Between the two visits, a lot happened. Shoutos training became harsher by orders of magnitude, and the pressure began to change him, warping his personality into what Endeavor thought he wanted. His mother continued to slip, the entire incident coming together when he startled her at the worst possible moment. A slip, her scream and then Shoutos own agonized screaming amidst a terrible hiss, and he was forever marked.
The scar defined a turning point in his life. His father showed no compassion or empathy towards him, continuing training as though his son hadn't almost lost all vision in one eye, and Shoutos hatred grew. Indeed, he probably would have turned out a powerful villain, had it not been for one more visit by All Might.
Unbeknownst to everyone, Yagi had well remembered meeting the child years before, and when it came time to think about a candidate to pass on his powers, that little child seemed like a possible choice. And so, he made an unannounced visit in the middle of the day to the Todoroki household, unaware of what had changed since his last visit.
He sat this time on a couch, facing Endeavor. "Thanks for letting me in, Enji. I know we've had our disagreements in the past, but I had a secret I feel I must entrust to you, and a proposition that you'll enjoy, trust me." He relaxed just a bit, Enji narrowing his eyes, his lip curling almost unnoticably underneath that flame beard he insisted on maintaining. "I doubt it. Tell me what it is you want so I can get you out."
Certainly not the type to beat around the bush. Yagis smile tightened. He wasn't on a time crunch, he had two and a half hours left to maintain this form currently. "Won't even be twenty minutes of your time. I've been invited to become faculty at U.A, something I have every intention to accept. I was thinking that your youngest, Shouto, will be ready to start curriculum there soon and I was wondering-"
At this, Enji stood, the flamed burning brighter. Somehow despite this, the atmosphere in the room was colder. "All Might, I let it go that you dare address me by my real name, but if you insist that my child needs your sponsorship to make it into U.A then I will beat you to death with my bare hands right now. He's going to get in, and he's going to do it on m-his merit. Understand?"
A typical response. Yagi didn't bother to match his height, raising his hands in apology. "I'm sorry, I never meant to imply such a thing, I was just interested in offering a hand if you'd like." He was met with silence, and so now he stood up, preparing to leave. Breaking the silence, however, was a shuffling of feet which made Yagi turn his head. And what a sight he saw. Standing just around the corner, same as he had all those years ago, was Shouto. But the only recognisable thing left about him was his hair. My, had he grown, double the height he'd last seen him at. His body was starting to fill out, his face surprisingly delicate for a child of Enji. Then, he met Shoutos eyes.
The burn mark was horrible. It was covered mostly by his fringe, but the scar tissue completely dominate his face around the left side, forcing his eye somewhat closed. His eyes were different in more ways than one, too. They held the same lack of warmth that Endeavors did.
Yagi looked over the boy once more, and that was the first time Todoroki Shouto saw All Might drop the smile. His eyes, previously dark wells of warmth and kindness, became hard as flint as he turned back to Endeavor, who certainly didn't look apologetic enough, something Yagi fully intended to change. "What did you do to him, Enji."
Endeavor growled, not backing down. "It was his ridiculous mother having a breakdown. She's been condemned to an asylum for what she did." Yagi breathed in deep. It wasn't Enji who did it, thank god. "Certainly did wonders to his personality though. After that, I was finally able to start training him for real. I didn't do it, but I should have thought of it years ago."
Endeavor managed to snatch defeat from the jaws of victory. A huge hand, bigger than he'd thought possible, shot across the coffee table and grabbed a fistful of his collar. The flames licking at his fist did nothing to deter All Might as he lifted the number two hero and dragged him bodily across the living room to face him. "Todoroki Endeavor, Your son is going to U.A and he is going to unlearn everything you taught him. I will personally make him a hero worthy of being the best and it will be through no work of your own.
Endeavor would have responded if All Might hadn't just reeled back and hooked him across the jaw so hard his neck almost broke, sending him into the wall so hard he almost went through it. Assured that the flaming asshole wasn't getting up for a while, Yagi turned to the child, his face softening up. "I hope you don't hate me for what I did just now, but trust me, your future is as bright as the sun, young Todoroki. I look forward to moulding you into an incredible hero at U.A."
Utterly confused by the sudden mood swing, Shouto could only watch as the man who just shattered his perception of his father politely walked through the front door, softly shutting it behind him.