Izuku knew that none of his classmates believed him about having a soulmate.
"You don't even have a quirk, Deku, and that was an 80% chance in your favour," Bakugou would sneer at him with a superior expression on his face. "What makes you think you could be one of the %5 of the population that has a soulmate?"
Their other classmates would titter, and whisper mean jokes to each other behind their hands.
"I'd prefer not having a soulmate at all, rather than having someone like Deku as my other half," was one of their favourite jabs, and each time Izuku couldn't help but feel his heart sink at hearing his greatest fear vocalized.
No matter how many times his mother told him that his soulmate (Toshi, he had asked Izuku to call him; a nickname from a friend he had met while studying in America) would love him no matter what, that they were made to complement him in every way, Izuku couldn't help the panic that would rise like bile up his throat at the thought of the man finding out about Izuku being quirkless.
So Izuku kept his quirklessness a secret from his soulmate.
His soulmate who was an amazing pro hero who had graduated from UA and spent his days helping save people from villains and who wouldn't want anything to do with stupid, useless Deku, if he knew just how pitiful he really was.
Izuku didn't think he would be able to bear it.
They didn't talk often – they couldn't, with how busy Toshi always was with his work, but he tried to be there when Izuku needed him, and was always unerringly supportive. He was Izuku's second favourite person in the entire world, and Izuku didn't know what he would do without him.
Izuku was pretty sure that his teachers didn't entirely believe he had a soulmate either, despite the fact that it was on his official record, and he even had the documentation to prove it.
That all changed, however, one afternoon when Izuku was just nine years old.
He was sitting in math class, not listening to a single thing the teacher was droning on and on about in favour of scribbling in his hero notebook about every little detail he could remember of the fight he had passed that morning on his way to school. So focused was he on his notes that he didn't even notice the teacher trying to get his attention until the person sitting in the desk next to his jabbed a finger into his side.
Jumping like a startled rabbit, Izuku zoned back into what was happening around him, only to see that his entire class were staring at him with wide, stunned eyes. Even the teacher was just standing at the front of the room, his mouth gaping and the piece of chalk he had been writing with drooping in loose fingers.
"I-Is something wrong?" asked Izuku, looking around uneasily, unnerved at all the attention focused on him.
"Midoriya, you…" the teacher started, then trailed off, speechless.
"What the fuck is up with your face, Deku!?" demanded Bakugou finally, when it seemed that no one else was going to say it.
"My face…?" asked Izuku, reaching up with his left hand to see if he could feel anything out of the ordinary, only to stop short as he noticed that all five of the fingers on his hand were bruised a deep, painful purple.
Flinching badly, he lifted his other hand and saw it looked the same as his left, with deep purple bruising and what looked like blood smeared across it.
The room around him was dead silent as he used one trembling hand to push his sleeve up, showing that the damage traveled all the way up his arm, and if Bakugou's words were any indication, it was on his face as well.
As his sluggish brain fought through the shock to inform him that he wasn't feeling any pain from any of the injuries, he suddenly realized what the bruises must mean.
"Toshi!" he choked out around a tight throat, tears gathering in the corners of his eyes.
This seemed to finally snap the teacher out of his daze, and the man immediately came rushing over to Izuku's side.
"Midoriya, we have to get you to the nurse's office immediately," the man ordered, taking hold of Izuku's shoulder with a gentle hand, urging him forward.
"I'm FINE," choked Izuku, pulling away from his teacher. He didn't want to be touched right now. "Th-these aren't mine!"
The tears were coming in full force now, accompanied with great, heaving sobs as Izuku stared in horror at his hands and arms. Frantic to see just how far the damage extended, he ripped open the front of his uniform shirt, and nearly threw up.
Red, red, red. All down his chest, his skin was stained a deep red, and there were what looked like jagged lines of torn fresh, but when he touched his fingers to the skin of his torso, it was smooth and unblemished.
His classmates were shouting around him now, and he couldn't make out what they were saying, but the distress was clear enough, and the teacher gave up trying to be gentle and all but dragged Izuku out of the classroom and down to the nurse's office.
Izuku wasn't sure what happened after that; he was too busy sobbing and trying to keep himself together, wondering if his poor soulmate was okay, wondering if he could possibly be alive, with all the blood Izuku could see staining his body.
Izuku wasn't sure how long he sat there in the nurse's office, but there was a lot of panicked shouting, a lot of distressed conversation between his teacher and the nurse, and someone telling him to breathe, to calm down.
And then, after what seemed like an eternity, the door banged open again, and there was his mother, standing in the doorway, still wearing her work clothes.
There was a strangled gasp as she took in the sight before her, before immediately dashing to her son's bedside and gathering him into her arms.
"Oh, my baby," she crooned into his hair, her voice breaking. "My poor, poor baby."
Izuku collapsed into her embrace, squeezing his eyes shut and sobbing.
After that day, no one ever doubted that Midoriya Izuku had been born with a soulmate.
Instead, the teachers just looked at him with pitying expressions, thinking what a shame it was, to have the blessing of a soulmate, only to lose them at such a tender age.
Inko took her son home early that day, and kept him home for a week.