Perhaps attempting to summon the strongest known familiar wasn’t the best idea Izuku has ever had.
Of course, this only occurs to him when a small tornado of red flames and biting icy winds roars to life atop the glowing summoning circle in the middle of his cabin. The initial burst is so powerful, he’s sent flying back, and he hits the wall and then the floor with a yelp, his back immediately aching with pain from the impact.
He barely manages to scramble to safety under his nearby desk just as the strong winds begin to tear apart his lab, scattering papers and knocking over supplies and throwing books off the shelves. He cringes when he hears glass shattering.
The desk above him begins to rattle and shake, and he swears he can smell burning wood. This is it, he thinks. His house is going to be burnt down by a wild familiar, and for what? So he could be like his idol? As if he could ever tame a familiar as strong as Yagi’s, much less one like this, who’s said to be even stronger.
His adoration blinded him to the risk of the situation, and now he’s paying for it. How pathetic, that this would be his downfall, that he would die hiding beneath a desk while his house is burnt, frozen, and burnt again by the double-sided monster standing a mere five feet away.
But then he hears something. A voice, so soft and fragile and quiet and yet still ringing out above the sounds of chaos around him. It whispers a single word, but Izuku can’t make it out, and before he can get a second chance, the wind is picking up even stronger than before.
That’s what makes him realize the source. That sweet little voice, a sound so delicate that it seems like it might shatter into sobs at any second - it came from the familiar.
He doesn’t know what was said, but he can feel the emotions behind it, and it fills him with a newfound determination. A sense of refusal, denial, rebellion. This is not the end, some part of him screams, and his eyes flick to the heavy iron collar lying a few feet away. He’d dropped it when he hit the wall, and it still lies where it landed, unmoved even by the creature’s terrible winds.
For just a moment, he moves out from under the desk and stretches one hand out to grab the metal ring. It’s unbelievably heavy, both physically and magically. It’s chock full of binding magic, made evident by the runes that glow golden along the inside curve as Izuku utters a spell. In response, the latch at the front comes undone, and the collar opens, ready to bind whoever wears it to whoever places it around their neck.
He knows he’s only got one shot at this. He’ll have to be fast, and he’ll have to go in strong if he wants to break through the spinning wall of fire and ice. It’ll be difficult and absolutely fucking terrifying, but he has to. He refuses to allow this to end any other way.
He just can’t give up here.
Breathing is hard, but he manages. He takes a deep breath, an attempt to steady his heart shaking his ribcage, and then he decides, go on three. He shifts into position, getting on one knee just behind the edge of the desk, hands tight around the open collar, head ducked and eyes focused on what he can see of the red and white whipping around.
And then he’s off.
He bursts forward, releasing all the tension in his muscles in that split second, rushing past the desk towards the familiar’s swirling shield. As soon as he hits the wall of the vortex, he feels it, the fire licking his skin, only to be cooled beyond soothing by the freezing winds a split second later. It hurts, and he screams, but he keeps pushing.
He pushes and pushes and pushes. He ducks his head and fights through the awful storm, and when his throat is too sore to scream anymore, he bites his lip instead, biting so hard it draws blood.
For a split second, no longer than a heartbeat, he considers giving up. He really considers it, just going limp and allowing the winds to whip him to the side so he can grab his spellbook and break the summoning circle. It’d be so infinitely easier than fighting like this.
But then he hears it again, for a second time, that sweet voice. That trembling little cry, on the very edge of breaking, like the stem of a flower that’s being pushed and bent by gale winds. It’s going to snap and break down at any moment, reaching its limits. All it needs is one more push, one more gentle breeze, and Izuku is filled with the urge to shield it from that cruel breath.
He hears it again a short second later, and this time, even under the roar of the winds assaulting his eardrums, he can finally make out that one little word.
It’s then that he realizes this is about more than just him. He’s only half of this equation.
It hurts, it hurts, it hurts, is all his brain can think, and yet he keeps going. He can see his goal now, the figure shrouded by the whirling terror, nothing but a blurred form in the center of it all. His eyes sting so bad, he has to close them, and he closes them tight, fearful the gusts of flame may burn them out of their sockets.
But even unable to see, he keeps moving, drawing closer and closer to his target, the cause of all this pain and mess, the only familiar he wants, his other half. He struggles and fights and cries until-
The collar locks into place around the throat of the eye of the storm, and suddenly, Izuku’s secluded little cabin in the woods is blanketed in silence once more.
For a moment, it doesn’t register for him. All he feels is the remaining sting from fire and ice on his bare arms and exposed face, and all he hears is his own heaving breath and pounding heartbeat.
But then, there’s a soft voice, one he’s heard before.
He startles and lifts his head, eyes snapping open to meet those of his newly-claimed familiar, and suddenly, he’s breathless for a completely different reason.
The demon is taller than him, a few inches or so, and he looks like a model. His expression is cool and even, maybe with a tinge of annoyance if the way his eyebrows are subtly pinched together is anything to go off of. His eyes, one a chilling shade of blue and the other a smoky gray, seem to stare straight through Izuku, sharp pupils cutting him like knives. His hair is dual-colored as well, half white and half red, no doubt representing those powers that beat Izuku so cruelly moments before.
And yet, more eye-catching than even those hypnotizing eyes or pretty hair, are the feline-esque ears that sit atop his head. Corresponding with the halves of his hair, one ear is pure white while the other is fiery red, but despite the danger Izuku now associates with those colors, the fur looks so soft. He’s nearly overwhelmed with the sudden urge he feels to rub those ears between his fingers, wanting to feel that velvety softness for as long as the demon will allow him.
He must stare for too long, as the cat familiar repeats with a slightly more demanding tone, “Hello??”
“O-Oh,” Izuku clears his throat and pulls his hands back from where they’re holding onto the sides of the collar fastened around the cat’s neck. “Sorry, um, it’s-” he wracks his brain for a moment before jutting his hand out, “-it’s nice to meet you! My name is Izuku.”
The cat looks down at his hand, back up to his face, and then off to the side. “I see.”
He feels a bit offended, but he holds back any comments, awkwardly lowering his hand. “Um, yeah. And your name is Shouto, right?” he asks hesitantly. “Shouto Todoroki?”
That earns him a sharp side-eye glance, the sort that would even have Katsuki flinching. “At least you did your research,” the familiar murmurs, and despite his cold eyes, his tone isn’t nearly as harsh or as condescending as Izuku was expecting.
The smaller boy’s shoulders slump a little in relief, and he offers a small smile. “Yeah, I mean, I would kind of need to know your name to summon you, haha,” he tries to joke and grins, only to rub the back of his neck sheepishly when Shouto looks away again, seemingly uninterested in kidding about.
“Why did you summon me anyway?” he asks quietly and turns away to approach the closest table, admiring the shaken but alive potted plants sitting there.
When his back turns, Izuku notices something else that really solidifies his connection to cats - a feline tail peeking out from under his button-up shirt, sprouting from the base of his lower back. It looks like the sort of tail a bakeneko would have, split in two a little less than halfway up its length. Similar to his hair and ears, one half is white while the other is red, and the colors meet at the split before continuing down evenly side-by-side until it reaches his skin.
Once again, Izuku feels the need to stroke his fur, to just feel it beneath his fingers.
He has to hold himself back from reaching out and taking hold of the two-headed tail, distracting himself by glancing away and admiring the damage his new familiar caused with his grand entrance. “Oh, uh, well, I needed a familiar,” he answers as casually as he can manage.
“And you chose me?” Shouto turns to look at him then, and so he automatically looks back, blinking when their eyes meet.
“Why?” Shouto frowns.
“Because I...needed a familiar..?”
“There are plenty of other familiars you could’ve chosen,” Shouto replies quickly, and yet his tone still remains even, not sounding snappy or even slightly inconvenienced despite how fast he spits the words out. “Why did you choose me?”
Izuku wonders briefly if there’s something more going on here. He wonders if that glimmer in his familiar’s eye means anything more, if its source is an emotion like hurt and betrayal or if it’s merely a devilish playfulness. He’s heard of familiars testing their masters, but somehow he doubts that’s what this is. It feels deeper, though that could just be Shouto’s serious expression making him think so.
Regardless, he takes a moment to think before he answers truthfully, “Originally, it was because I wanted to have a strong familiar like my idol, the warlock, Yagi. I’ve always admired him, and so I wanted to be like him, so I chose the strongest familiar I could find, which was you.”
The way Shouto’s expression falls is telling.
But Izuku goes on, “But then I heard you.”
The familiar looks up, and for the first time, a clear emotion spreads across his face - surprise.
Izuku offers a little smile. “I was about to give up, twice, but both times, you spoke to me. You said please. That’s when I knew-” he takes a breath, “-it had to be you. You’re my familiar.”
When the familiar’s cheeks warm with a cute blush, he decides pink is a nice color on Shouto.