Chapter Text
He may, in fact, have a problem. Izuku considered this as he stared down at the tooth sitting in his palm. A problem indeed.
He hadn't thought much of it at first, he had had so many other things to think about it seemed trivial among them. After all, he was ten, and he was still in the process of losing some of his remaining baby teeth. So when two of his canines had fallen out about a week ago, he wasn't alarmed.
His mouth had begun hurting on and off a while back, his gums feeling sore on occasion. But compared to all the other, more apparent, transformations his body was going through, he had been a bit preoccupied. More preoccupied with the small, tender bumps on his head that had grown into horns. More preoccupied with the newer, longer ears he had woken up to the one day. More preoccupied with the small scales that had begun popping up under his eyes and on his hands and arms. And definitely more preoccupied with the new appendage he had sprouted recently, his tail having been the most troubling of them all.
But now, as he stared down at the tooth in mild horror, Izuku decided he should have paid more attention. The tooth that had just fallen out was one of his front teeth, a tooth he had already lost a couple years ago.
So, staring down at the adult tooth that had just fallen out of his mouth like it was nothing, Izuku decided this was, most assuredly, quite a problem.
He clenched his hand tightly around the tooth so as not to lose it, slipping out of the room he had been cleaning to go find a mirror. Upon successfully locating one (and successfully ignoring all of the other nonhuman features staring back at him) he took a moment to examine his mouth in the dim lighting available.
...His canines were sharp, sharper than he thought should be normal for a human. His gums were reddish, looking sore and somewhat inflamed. There was a gap in the front of his mouth now where his front tooth had just fallen out, but when Izuku tilted his head back he could see a small, pointy, white bump beginning to emerge from the gum-line where the now empty space was.
Dragon teeth? Dragon teeth.
He was growing dragon teeth.
Well, at least now he knew why his mouth had been hurting for days. Izuku ran a hand through his hair raggedly, clutching his horns with a muffled scream of frustration. He was tired all the time recently, the physical transformations he had been going through were not easy on his body. Coupled with the daily labour he was subject to at the bathhouse, the lack of food he was eating (or not eating really) in a futile attempt to slow down his transformation, and the mental exhaustion of having to deal with Lord All Rivers In One constantly hounding him and trying to steal him away at any given opportunity, well. Izuku could say he was feeling more drained than he had ever felt before in his life. The temptation to just curl up in one of the steaming hot baths when he was supposed to be working was getting harder and harder to resist, his body craving to bask in the heat the way he had seen his old neighbour's cat do in the sun.
But he had been lingering in front of the mirror for too long now, best to get back to work before he got in trouble.
A few days later and Izuku could not have been in a worse mood. His mouth hurt like hell, more teeth having fallen out and stronger, sharper ones emerging in various stages of growth to replace them. He still hadn't gotten used to his tail, often forgetting he even had one and consequently either tripping over it, knocking things over with it, or having it stepped on because he didn't think to move it out of other's ways.
And to top off today? That dreaded, overgrown snake had come back from whatever trip he had been on. With, as usual, his first course of action being to waltz in to the bathhouse to annoy Izuku.
Except this time he couldn't even use the excuse of having to work to try and get away from the dragon; Lord All Rivers in One had specifically requested Izuku's presence as company—for the next couple of hours. Izuku's eye had twitched madly upon hearing the news. He had errands to run today, packages and letters to deliver, baths to clean. And now his whole schedule was going to be crammed into an evening of speed work trying to catch up on all of his tasks once Lord All Rivers in One was done with him.
Currently, however, he was sitting on a blanket in front of a small feast next to the largest bath the bathhouse owned. All Rivers in One sat across from him, looking unfairly pleased with himself. "You are allowed to eat, you know," the dragon said, "I had all of this brought for you."
"My apologies, Lord All Rivers in One." Izuku was aware he didn't sound very apologetic at all. "It would be inappropriate of me to eat on the job."
The dragon hummed in amusement. "Would it?" He asked, "I should think it would be more inappropriate for you to not fulfill a paying client's wishes. You wouldn't want to make the witch unhappy by upsetting her patrons would you?"
Izuku's lip curled in irritation. The dragon was taunting him. "Of course not," was all he replied, reaching forward reluctantly to pop a few grapes in his mouth. He chewed carefully, trying not to aggravate his sore mouth too much. "This is quite an unusual request for a guest to have though."
All Rivers in One sipped his tea, his eyes glittering with something Izuku couldn't parse out. "Perhaps. I've been gone for over a week though, surely you've missed me as much as I've missed you, my Little Stream."
Izuku snorted, fat chance, the past week had been one of the most peaceful he'd experienced so far in the spirit world. Barring all the new transformations he had gone through recently of course. "Has it only been a week? Pity," he mumbled quietly.
"Hm? What was that?"
"Nothing!" Izuku shook his head, shoving some more food into his mouth to avoid having to answer fully, wincing at the pain it caused.
"Good, good." The dragon smirked. "I'm certain your boss wouldn't want to hear about her employees being rude after all."
"...Are you threatening me?" Izuku asked, a small growl trying to crawl it's way out of his throat.
"Of course not!" All Rivers in One waved a hand dismissively. "Though, you have been rather grumpy today, Little Stream. Is something bothering you?"
"You mean other than yourself?" Izuku fired back before he really thought about his words. The dragon bared his teeth at him, though it seemed more a playful warning than truly aggressive. Izuku instinctively bared his back, hand flying up to cup his jaw at the stab of pain the movement caused.
All Rivers in One froze—momentarily impressing Izuku with his ability to mimic a statue—before he leaned forward, eyes sparking with interest. "What was that?" He asked, a smile curling across his face.
"What was what?" Izuku played dumb, his tail jumping where he had it bound beneath his robes, wanting to flick about in response to his annoyance.
Lord All Rivers in One seemed perfectly fine ignoring both social conventions and personal space, using his unfair height advantage to reach out and pull Izuku across the blanket and into the dragon's lap. Izuku squawked at the manhandling, and All Rivers in One used it as an opportunity to stick his fingers in Izuku's mouth, prying it open.
Izuku thrashed angrily in the dragon's grip as he crooned, looking delighted. "Oh, Little Stream! Look at those tiny, sharp teeth!" The dragon intently studied Izuku's mouth, running a finger along reddened gums. "No wonder you're so grouchy," he murmured sympathetically, his other hand carding through Izuku's hair. "Poor baby, your mouth must be so painful. It's alright though, Papa's back, I'll help you."
Izuku bit down on the hand in his mouth in aggravation, but he couldn't even pierce the dragon's skin. All Rivers in One simply laughed, cooing at him. "Such strong teeth you have! What a fierce bite!"
Izuku immediately spit the dragon's hand back out, even if biting down on it had, oddly enough, helped relieve some of the pain. This was still All Rivers in One, the spirit who took his mother and kept trying to take him as well. He wriggled in the dragon's hold, trying to get out of his lap. The arms around him were like solid steel however, and it didn't seem like escape was looking good for Izuku today.
His struggling did loosen the tie around his tail though, and it lashed out, smacking the dragon harshly in the side. All Rivers in One startled enough for Izuku to slip off his lap, quickly backing up and out of immediate reach. The dragon's stare was fixated on his new tail, eyes wide.
There was a tense moment of silence between them, Izuku becoming more wary as the dragon grew more excited. "Look at you!" All Rivers in One positively purred, "Why, I dare say you'll have your first full transformation in less then a week."
Cold dread filled Izuku at the proclamation, and he dodged to the side as the dragon lunged for him. He managed to hold out for a minute or two, avoiding the dragon's attempts to grab him. But there was only so much he could do against a being who had an extra limb, and sooner than he would have liked, All Rivers in One had caught him by the waist with his tail, depositing Izuku back into his arms. Lord Shigaraki snuggled him close, stretching out Izuku's tail to admire it.
"You are absolutely adorable, Little Stream." The dragon was careful as he ran his hand over the length of the tail, sending shivers down Izuku's spine with the sensitivity of the new limb. "You are also clearly in need of quite a bit of care. Luckily for you, I have experience with tending to little hatchlings like yourself."
"I don't need your help! And I'm not little," Izuku huffed, continuing to wiggle about in the dragon's grip despite the height he would fall from if he got free.
All Rivers in One clicked his tongue, looking amused. "Ahh, that's right, I forgot. You fancy yourself a mini adult." He booped Izuku's nose, uncaring of the scowl the boy sent him.
"I don't fancy myself anything, I'm ten years old, I'm not a child," Izuku hissed back.
"I hate to inform you, Little Stream, but only hatchlings have soft scales like this." Lord Shigaraki tapped Izuku's scales pointedly. "You," he said, holding the boy aloft, "are a baby dragon."
Izuku had been surprised to find his scales were softer than he had expected. They weren't by any means as soft as skin or easily breakable, but they lacked that diamond hard quality All Rivers in One's scales had. Izuku had assumed it was simply because he was supposed to be human. "I am NOT a dragon," Izuku protested.
And yet, he feared Lord Shigaraki was right. He feared his loss of humanity.
"A grumpy baby dragon," All Rivers in One amended, pulling Izuku back to his chest. "We'll need to treat and buff your scales so they'll grow strong and shiny. I'm sure I have something to help ease the pain in your mouth as well, I did keep all of..." The dragon trailed off for a moment, eyes distant and face haunted with sorrow. "...all of your old things after all. In fact your room is still waiting for you exactly as you left it."
Izuku didn't like the way that sounded at all. The dragon was clearly desperate to pretend Izuku was the son he had lost. It chilled him.
"I'm going to have to decline," Izuku spoke carefully, "I have other duties to attend to once the time you've paid for is up."
Lord Shigaraki pinched the bridge of his regal nose in frustration. "Why do you insist on this facade, Little Stream? I know you'd rather come home with me, what child doesn't want to be pampered? I have everything you could ever want waiting for you: toys, beautiful clothes, a luxurious bed, delicious food...and your mother of course."
Izuku would be tempted if he didn't know the cost to such an offer. "Would you like me to fetch some bath tokens, Lord All Rivers in One?" He changed the subject without even blinking. "You haven't yet taken advantage of our baths, and you really should get the most for your money."
The dragon eyed Izuku with displeasure, but surprisingly set him down. "I suppose a nap will do you some good, yes. Run along and fetch those tokens then."
Izuku did so swiftly, confused by whatever Lord Shigaraki meant with his nap comment. He determine to put it out of his mind as he slipped back into the familiar role of his job, filling the bath with boiling water and adding in some scented oils. All Rivers in One shifted into his dragon form, curling his large body into the bath comfortably. "Come here child," the dragon called.
Izuku reluctantly obeyed, stopping near the lip of the bath. "What can I assist you with, Lord Shigaraki?"
He didn't notice the tip of the dragon's tail sneaking up behind him until it knocked him forward. Izuku fell into the bath with a yelp, surfacing quickly to glare at the stupid lizard that kept toying with him. He stuck his tongue out, receiving a deep chuckle in return, and attempted to swim back to the edge of the bath. The steaming water was nice actually. Too nice, and Izuku could feel his body involuntarily relaxing, wanting to curl up in the heat. He was feeling a bit drowsy actually, which indicated he really had to get out before he did something stupid like fall asleep.
Except Lord Shigaraki wouldn't let him.
The dragon circled his body around Izuku, so no matter which way he turned he couldn't reach the edge of the bath, All Rivers in One's large body a barrier he couldn't get past.
"Settle down, Little Stream," the dragon crooned, ducking his head under Izuku. Izuku ended up clinging to his snout, getting too tired to keep treading water as all his attempts to escape were thwarted. The pull of sleep was strong with such a hot temperature around him, something inhuman in Izuku purring at the heat. "That's it," Lord Shigaraki encouraged as Izuku's eyelids grew heavier. "Relax, enjoy your nap."
Izuku grumbled something unintelligible, hardly even noticing when All Rivers in One transferred him onto his back, watching contentedly as the sleepy hatchling curled up, falling asleep as soon as he was comfortable.
Izuku woke up slowly, snuffling into the soft blankets he was cocooned in.
...Blankets?
He was upright within seconds, taking in the room around him with wide eyes. It was large, with soft, pastel purple walls painted by warm sunlight coming in through a large window. There was an elegantly carved, wooden toy box below the window, the lid open and showcasing a confusing mix of toys for different age ranges. Izuku could see a few toys that—he didn't want to admit—he may have been interested in, right next to toys that better suited a child half Izuku's age.
A large bookshelf took up most of the expanse of one wall, with a little reading nook carved into the wall nearby filled with fluffy blankets and pillows. The bed Izuku currently found himself in was...well, it was almost more like a bowl than a normal shaped bed. It was large enough to allow a young dragon to curl up in, and filled with plush, soft blankets and pillows. One section of the...walls? Frame? Of the bed was missing to allow entrance and exit of the nest. It was also suspended slightly off the ground, and Izuku followed the chain like supports with his eyes, looking up to notice different star constellations and murals of dragons and rivers twinkling on the ceiling.
It was a nice room.
So of course Izuku immediately bolted for the door.
...Which was locked.
He huffed and instead turned to the window above the toy box, shutting the lid to climb on top of it and peer out. He was...very high up. And unless he somehow learned to fly within the next five minutes he wasn't going to be able to escape that way.
The click of the lock grabbed his attention and Izuku spun around as the door opened, Lord All Rivers in One smiling when he caught sight of him. "Ah, Little Stream, you're awake. Good, I found just the right salve for you."
Izuku eyed him warily, there was a lot he wanted to say right now. Questions to ask, accusations to fling. But what came out of his mouth first was: "Salve?"
All Rivers in One held up a small jar. "Yes, this salve should help to numb and ease the pain from your teeth growing in." The dragon plucked Izuku off the toy box with his tail, sitting on the edge of the plush bed and placing the boy on his lap. He dipped a finger into the salve, tilting Izuku's head up with the other hand. "Open nice and wide for me, Little Stream."
Izuku attempted to pull his head back, but the dragon had a firm grip on his jaw. "I can do it myself," he protested through clenched teeth.
All Rivers in One sighed in exasperation. His tail was still wrapped around Izuku's waist, keeping him in place. He moved his hand, pressing into the sides of Izuku's cheeks to force his mouth open. Izuku did his best to resist but was easily overpowered by the large spirit. Instead he settled for glaring venomously as All Rivers in One began to rub the salve on his irritated gums.
The urge to bite down on the dragon's hand again was almost overwhelming. Though strangely, this time the urge didn't stem from anger and a desire to cause pain. It was more of an itch, an instinctual compulsion to bite down on something and feel the resistance against his teeth.
Weird.
"Huur ahp!" Izuku grumbled as best he could around the dragon's hands.
"I could do this much easier if you'd agree to sit nicely and cooperate," Lord Shigaraki chastised him.
Izuku crossed his arms and huffed. "Fine."
All Rivers in One shifted back, allowing Izuku to massage his sore cheeks and jaw where they'd been held open. He looked up at the dragon as the dragon dipped back into the salve. "Just the upper gums are left." Lord Shigaraki sounded far too cheerful about this in Izuku's opinion.
Still, he tilted his head up and opened his mouth of his own volition, trying to keep still as the dragon began to rub more of the salve into his gums. "Your teeth shouldn't take too long to come in, I'd estimate within a week you'll have them all. Likely around the same time you experience your first full transformation."
Izuku grunted but said nothing, letting Lord Shigaraki continue. Begrudgingly, the salve was working. There was less of an overall ache, and the swollen areas where new, sharp teeth were beginning to poke through were numbing.
And yet he still couldn't shake that incessant itch to bite.
"All done," All Rivers in One announced with an affectionate smile. "Now you can have this." He reached into the folds of his robes and pulled out a...toy?
Izuku stared quizzically at the thing being presented to him, face scrunched in confusion. It was circular, in the design of a long dragon looping around itself, jaws clenched on its own tail. It seemed to be made of rubber or silicone or something of the like, not that Izuku could figure out what the damn thing was for.
All Rivers in One held it up to his face, shaking it invitingly. "Go on, I had it chilled a bit to help with the numbing effect on your gums."
Oh. It was...
"Is that a teething ring," Izuku hissed in outraged disbelief.
Lord Shigaraki simply blinked. "Of course."
Izuku's mouth opened and closed wildly as he tried to formulate a proper response. "I'm—that's, what—it's..." He scowled. "Those are for BABIES!"
The dragon snorted. "It's perfectly normal for young hatchlings like yourself to use as you grow your adult teeth. The counter pressure will help to relieve some of the pain. I'm certain you've been wanting to bite into things the past few days, correct? All baby dragons do; you're growing your stronger, permanent teeth that will allow you to rip apart your prey down to the bones. Your instincts are naturally kicking in in preparation."
"I'm not using that! I'm not an infant!" Izuku snarled back.
All Rivers in One squinted in...confusion? "Of course you're not, why would I even give a teething ring to an infant?" He asked incredulously. "They wouldn't need it."
"What?" Izuku scrunched his nose.
The dragon cocked his head, staring down at Izuku contemplatively. "I think," he began, "you are applying human standards to dragons. Newborn dragons are born with teeth, Little Stream. It's not until around your age they begin to lose their baby teeth and grow their permanent adult teeth." He held the ring closer to Izuku. "This is a perfectly age appropriate item."
Izuku crossed his arms. "So then I'm NOT a baby."
"No, no. You are definitely not an infant, but you are still a baby," Lord Shigaraki corrected cheerfully.
Izuku's eyes fixated on the teething ring in front of his face. Species growth standards or not, it still felt demeaning. It was humiliating, Izuku was not a dragon, and he was not a baby, and he was most definitely not a baby dragon. He hated it.
And he hated how much he wanted to bite down on it.
"Oh just take it, Little Stream. You've had to suffer this whole week while I've been gone, let Papa help you take the pain away." All Rivers in One pressed it against his lips.
And Izuku involuntarily snapped his jaws around it, biting into the material aggressively, an inhuman growl emerging from his throat.
Lord Shigaraki cooed. "Aww, my Little Stream already has such good predator instincts."
Biting and grinding his teeth against the cool ring felt good. It shouldn't, Izuku thought, he was acting like some sort of rabid dog with a new toy. But he couldn't make himself stop.
Lord Shigaraki was purring, nuzzling his face into Izuku's soft, fluffy hair. The deep vibrations of the purr seemed to seep into Izuku's bones, making him relax against his own wishes. He sagged against the dragon's chest, some foreign feeling inside of him rising up in response to the adult.
Izuku chirped.
And dropped the ring in shock, hands flying up to cover his mouth. That sound...shouldn't have been physically possible for him to make.
All Rivers in One looked elated, eyes reflecting a soft awe. The dragon let out a low crooning noise, and Izuku instinctively chirped again in answer. He suddenly found himself airborne, All Rivers in One having flopped on his back on the bed, holding Izuku up above him at arms length. The dragon laughed with delight, even as Izuku stared down at him unimpressed.
"It's been far too long since I've heard the chirp of a hatchling," All Rivers in One sighed, a thread of melancholy in his tone. Izuku was too embarrassed to respond, staring down at the dragon flatly, his cheeks flushed. Lord Shigaraki's tail suddenly appeared in Izuku's face, tickling under his nose, and Izuku's eyes locked on to it—as did his teeth.
All Rivers in One just chuckled, seemingly unbothered by Izuku's attempts to chew through his tail. Izuku bit harder in retaliation, annoyed at being mocked, but the scales beneath his teeth had no give, and scraped unpleasantly against his teeth and sore gums, causing him to quickly release it. The tail ducked out of sight only to reappear moments later holding out the ring again, and Izuku begrudgingly accepted it.
He was already humiliated at this point, how much more could the dragon make fun of him anyway? All Rivers in One abruptly dropped him, Izuku landing on his chest with a squeak of surprise. The dragon's arms cradled around him and he let out a low grumble of annoyance. Lord Shigaraki snorted in amusement. "Sorry, little one, did you like being up high? I can put you on your cloud if you want to fly."
Izuku paused his chewing. "Cloud?"
Lord Shigaraki stood smoothly with Izuku in his arms, and waved a hand in the air. Izuku watched curiously as a small, fluffy, white cloud floated down off the top of one of the bookshelves, hovering in the air in front of them. Izuku tensed as All Rivers In One moved to set him down on the cloud, but he didn't fall through it.
The cloud was solid, and actually incredibly warm and soft. Another small chirp emerged from Izuku's throat as his body flopped down in the cloud, nuzzling into it happily. A clawed hand landed in his hair, scraping gently against his scalp, and Izuku leaned into it, his head feeling light and fuzzy. He yawned, blinking heavy lids before shaking his head aggressively, trying to clear the haze in his mind.
"Go back to sleep, Little Stream," Lord Shigaraki encouraged softly, cupping his cheek.
Izuku sat up straight and rubbed at his eyes. "But I was just sleeping, I shouldn't be tired."
"It's normal, your body is preparing itself to change forms soon, you're going to be sleeping a lot more leading up to it."
The cold shock from such bad news helped Izuku to feel more awake. He didn't have much time left, he had to find his mother and get out before it was too late for him to leave.
"...Where's my mom?" He asked curiously.
The dragon smiled at him warmly. "She's around. You don't have to worry about her, Little Stream, she's perfectly fine."
"I want to see her," Izuku insisted.
Lord Shigaraki twirled one of Izuku's curls around his finger. "You'll get to see her, right after you finish your transformation. Just relax and focus on staying healthy for Papa, ok?"
"No!" Izuku scowled, slapping the dragon's hand away from him. "I want to see her now!"
All Rivers in One frowned disapprovingly. "She'd just be a distraction to you right now, Little Stream, she can't care for you properly during this time. She doesn't have any experience in helping baby dragon's learn to shift."
"She's not a DISTRACTION!" Izuku shouted back, punching the cloud with one small fist for emphasis. Distantly he was aware of how childish he was acting—he was ten years old, he knew better than this. But he was tired, and the emotional control he so prided himself on was slipping.
Lord Shigaraki 'tsked' and crossed his arms. "That's quite the temper tantrum, you're throwing Little Stream. Are you looking for a time out?"
"No!" Izuku rubbed at his eyes again, they burned with tears and exhaustion. He heard the dragon sigh heavily, and he was plucked off the cloud without warning.
"You definitely need another nap," All Rivers in One murmured, cradling Izuku's head against his shoulder.
"Put me down!" Izuku protested, even as his eyes drooped.
"Little Stream, I will put you in the timeout corner if you continue to be so petulant."
"Whats petulant mean?" Izuku asked drowsily, his tail unconsciously curling around the dragon's wrist.
"It means sulky, bad tempered, moody," Lord Shigaraki explained patiently.
"Oh. Rude." There was a long moment of silence, Izuku almost drifting off from where he was being rocked in the dragon's arms. He shook himself back awake, pushing against All River's in One to try and free himself.
"Shh, Little Stream, stop fighting," Lord Shigaraki coaxed, easily keeping his hold on the little boy.
"That's not my name!" Izuku hissed, fed up with the dragon. He realized his mistake the moment a dangerous, toothy smile was sent his way.
"No?" All Rivers in One cupped him under the chin, forcing Izuku to meet his eyes. "What is your name then, sweetling?"
Izuku's mind raced. He couldn't back out of this now, refusing to answer would do no good. Lord Shigaraki would never let this go. "It's uh, Deku," he said, throwing it out quickly.
The dragon's nose scrunched as if he ate something sour. "Deku? Well that's not very pleasant." He looked at Izuku considerately, a gleam of something Izuku couldn't define in his eye. "No, no. That won't do. I won't be calling you that. You're Izuku."
Izuku felt like he had been dunked in ice water. The dragon had known his name this whole time? How? When? Had he been playing with him all along?
All Rivers in One set Izuku back down on the bed. "Yes. Deku could be read as Izuku with a little tweak after all. Much nicer, don't you think, baby?"
So he...didn't know then? Izuku was confused. He just wanted to sleep now.
He didn't answer, rolling over and turning his back to the dragon. Lord Shigaraki chuckled, tucking him in and kissing his temple. "If you need me, knock four times on the door and I'll be there."
And then Izuku was finally alone again, trapped in the dragon's home, his window of escape narrowing with every passing minute.