There is some part of Izuku that wishes that he had struggled more, held fast to his true faith, and fought the demon off like he was flimsily trained to do. If it had been any other demon, any other god, he feels pretty sure that he could have done so.
Katsuki is unlike anyone or thing he has ever come across or even heard of.
For all that he is cruel, conniving, and, well, horny, there is an intelligence and wit that Izuku remembers so clearly from their time on the frontlines. There is a reason why the dreams from then, while alarming as they were not appropriate for a man of the cloth to be having, the nature of them wasn’t surprising.
Even before seeing Katsuki again in front of the inn in Musutafu, Izuku loved him a little bit. Now that he thinks about it, it is probably what got him so deep so fast. That isn’t to say that he is 100% on board, part of him, smaller every day, worries that all that he is feeling is a manipulation of the demon’s. Izuku had seen with his own eyes how easily the demon convinces humans the sky is red.
He knows there is no going back, he doesn’t want to go back. It is like his life prior to this was all in grayscale and Katsuki introduced him to color.
The demon, soon to be God explains that the Ascension will take place at the end of the year, during the darkest night. Besides that, Katsuki has been very tight lipped about what the ritual entails, worrying the anxious priest to no end. When he tries to bring it up, the demon pats his cheek and says that all will be revealed in due time.
Every day that brings that moment even closer. Outside, the world begins to die off. They leave the harvest season, and dive headfirst into winter. Izuku has always found winter to hold a barren kind of beauty, and the woods near Musutafu are a clear example of that beauty. The trees have long been stripped of their leaves, leaving space for the snow to fall through, littering the ground in soft piles. Out of all the places he has lived over the course of his life, Musutafu has one of the milder winters.
It makes wintery walks like this one enjoyable instead of miserable.
Normally, he doesn’t venture this far from home, even during the summer and spring, but he is on a mission for snowberries. The sweet tart berries make a wonderful jam, that makes for an excellent Winter Festival gift. All the places that he normally forges for it, have already been picked clean by hungry birds and deer. Truth be told, he has no idea if he is actually going to be able to celebrate this year, as the festival is held on the last day of the calendar year. He has no idea what state he will be in after the ritual. Without knowing for sure, Izuku has decided to just carry on like nothing will really change for him.
As he works, the shadows around him begin to grow long in the lingering light. He’ll need to turn back soon, if he is going to make it home before it gets too dark. Izuku doesn’t really want to see how pissed Kacchan will be if the demon has to come looking for him. For being an immortal being, he is a bit of a worrywart. More so every day that brings the end of the year closer. Izuku is picking the last of the ripe snowberries from their bush, when he realizes he is no longer alone.
A hush settles over the forest, Izuku has never heard the woods so quiet. Not even the wind rustles the trees. The sudden absence of noise leaves his ears ringing, it also alerts him to the sudden scent rolling through the clearing. It is unnatural, hanging heavily in the air, it stinks like someone has left an empty kettle over the flame, burning, and twisting the metal, laced with the sweet scent of rot.
Standing, he turns to see a figure through the trees. It has definitely seen him because it’s head swivels in his direction and it begins to hobble his way. It is passable as a human, but only passable. Truthfully, the only way someone could look upon it and think that it is human, is the person looking at it didn’t believe in demons. For that is what it is, Izuku knows without a shadow of a doubt.
Its skin is an unhealthy pale color, a sickly yellow color blooming in sections where it is pulled too tight against bones. Dirty hair clings to its face, clumped together with grease and debris. The clothes it wears hang off its body, worn and gross looking, stains covering them.
Despite all of the warning signs, Izuku finds himself unable to move, fear anchoring him to where he stands, heart beating against his ribcage. It shuffles closer and Izuku can see its horns ripping through its scalp like paper, as if the human skin it wore no longer can hold back the demon’s true form.
“Hello,” It says, face twisting into a facsimile of a smile, “I knew there was a settlement nearby, but I didn’t think someone’s pet would be wandering the woods alone. You get lost, little doggie?” It laughs, and it is a harsh grating noise.
Izuku barely is able to take a couple steps back, every inch a struggle, clutching his basket of berries close to his chest. It isn’t enough, and the demon suddenly moves much faster than before, one moment it is several yards away and then the next it is crashing against Izuku. He loses his footing and sprawls helplessly against the snowy ground, his basket sliding away from him. Izuku has no idea what is going on with his body, why can’t he move?
“I wonder whose pet you are. Your master will be looking for you soon, but I imagine they won’t mind if I have a little snack before helping you home.” It comments, it’s voice rough from misuse, as it crawls on top of Izuku’s unmoving form.
“W-What are you talking about?” Izuku forces out through uncooperative lips,
It blinks its yellow eyes at him, a spidery hand resting heavy against Izuku’s stomach. “I can smell the demon cum in your belly, little doggie. You must serve your master well. I had planned to set fire to the nearby village to keep topside, but a snack wandering in front of my path is providence.” It leans down and runs a dry tongue against Izuku’s face.
The green hair man screws his eyes shut, trying to get his body to move, to at least fight off the demon. It being this close, the stench is overwhelming. From the sound of it, it will return him to Kacchan afterwards, but Izuku doesn’t want this, what will Kacchan think?
With a jolt, Izuku realizes that even though he is an hour or so from home, he can still pray to Kacchan and maybe the demon will get to him before the other demon does too much damage.
Kacchan please help me, there is another demon and I am scared of what it is going to do, please Kacchan, help. Degust and fear rake his body as it begins to snake its emancipated hands underneath his clothes, and he uses those feelings in his prayer. He chokes down a sob as sharp fingers tease a nipple. Revulsion curls in his stomach, and he wants nothing more than to be able to run, but he can’t.
There is a crack, loud and deafening, and suddenly the weight that was pressing Izuku into the snow is gone. Green eyes open hesitantly, to find the forest around him on fire. Flames cling to the trees and the ground, melting the snow and scorching the earth. Across the clearing the demon is crumbled against a smashed tree. Standing between Izuku’s prone form and the offending demon, is Kacchan.
Izuku’s demon and soon to be god is wreathed in the fire, his form stretching and twisting, shedding his more human appearance for a more demonic one. Claws tip his large hands, his four horns out in all of their glory, his thick black tail whipping to and fro like an angry cat. The yellow eyed demon groans as it sits back up, body crunching back into shape after Kacchan had apparently thrown it into the tree.
“Fuck, what a rude way to say hello,” It spits, browned blood trickling from its lips, it focuses its glare on Izuku’s demon “You look familiar...Oh, you’re, um Bakugou right? Figures such a cute little doggie topside would belong to you,”
“If you know my name, you must be really fucking stupid. You come into my territory, unannounced, and think you can feed from what is mine,” Kacchan hisses, his form now standing easily over eight feet tall, not counting the height given by his horns. Smoke curls from clawed hands,
“How is it any different from the ones you send below?” The demon asks, clearly confused.
“The difference is this one is mine, is marked as mine, and you will pay for touching him,”
The other demon snorts, rolling its eyes, “Whatever, I am at my limit anyways, send me below. I’ll be back though; we’ll see how confident you are when I am at full strength. I want a taste of the little doggie and I do end up getting what I want,” It promises with a sickening smile towards Izuku who is still sitting in the snow.
Katsuki roars, covering the distance between him and the other demon in an instant, grabbing it by its throat. Izuku cannot see his demon’s face from where he is, but he can hear the malice in his voice as he speaks again, “Oh no, I am not sending you underneath, the punishment for touching what is mine is death. True death.”
As his demon speaks, the air pressure in the little clearing rises, leaving Izuku’s head aching and his vision swimming. The offending demon’s eyes bug out of its skull as it begins to properly struggle, screeching, screaming, begging for mercy, all earlier bravado gone as it uselessly claws at Kacchan’s large hands as the pressure continues to rise. Then, as it reaches its crescendo, almost too much for Izuku’s human body to handle, it breaks, as does the demon. It dies with an abrupt ending scream. An inky darkness stains the ground below where the demon had been.
Just as the pressure breaks, so does the weird spell that had been holding him hostage. His body sags in relief.
“Kacchan?” Izuku hesitantly asks, and his demon turns his large head towards him. A deep growling fills the now safe area, not as aggressive as it had been, but it still sends a chill racing up Izuku’s spine.
He had been living with Kacchan for almost three months at this point, and he had never heard such inhuman noises from the demon. For the most part, it had been easy to forget that at his core, Katsuki is not human, because of how he acts and looks.
This form before him now, lacks the comforts of humanity. His eyes are completely red, except for his slitted pupils which are a bright glowing white. Kacchan’s movements are odd, jagged, as if Izuku’s eyes can only follow every other movement as he moves back to him. The demon lowers itself to the ground, so that it is eye level with Izuku who is still sitting on the ground. Even crouched, this new form looms over Izuku.
Tears well up in his eyes, as he tries to calm himself down. Hands as large as his head cup his face, and Izuku cannot help but lean into the heat. So desperate for the contact coming from a trusted source. Why had he been unable to move? He had been so terrified.
“Deku,” Kacchan growls through a mouthful of razor-sharp teeth, rubbing his cheeks heavily against the spot where the other demon had licked. Trying to erase the stench of burning metal, replacing it with the must more comforting smell of pine and caramel. The demon shifts, pushing Izuku’s fragile human body back into the snow. At his current size, Katsuki dwarfs Izuku, the human feels almost childlike against the girth that the demon is.
With hands tipped in razor blades, Kacchan leans down and rips open Izuku’s clothing, leaving him mostly naked in the snow. The human lets out a gasp in shock as the cold air hits his now exposed chest. Kacchan’s mouth, filled with its new rows and rows of very sharp teeth, latches onto one of his nipples. The cold air makes his chest all the more sensitive.
Izuku really doesn’t know what is going on, and why Katsuki is being so weird, but he really doesn’t think at this point he has a say in what the demon is doing. Deft fingers creep up to the unattended side, causing a moan to rip from his mouth. Freckled hairs reach up, carding through soft blond hair before holding onto the demon’s horns as Kacchan continues to assault his nipples.
Delicately, Katsuki catches the tip of the nipple between his teeth and pulls. Magic swirls between them as the demon continues to pull at Izuku’s chest, slowly but surely, causing his already perky chest to swell with the effort. Not allowing the human much time to come to terms with the new size of his chest, the demon switches sides. The swelling isn’t nearly as large as most women in the town, but it is definitely not just a flat chest anymore. Large enough, however for the demon’s hot hands to grab and squish.
“Do you like that, slut?” Kacchan growls out, his voice barely understandable through the territorial growling noise he makes. The demon kneads the human’s new breasts, like one would milk a dairy animal.
It takes mere moments before Izuku has broken down into whiney sobs. The noises spur the demon on, leaving the priests skin red and raw.
Katsuki releases one of his breasts, and heads towards his ass, rudely shoving two large fingers into the wet waiting heat. Izuku screams, cumming at the internal stimulation, limply relaxing further into the snow.
“Such a wet fucking bitch,” the blond mutters to himself, effortlessly pulling Izuku’s ass up into the air, his legs uselessly hanging on either side of his face. A tongue, longer and more dexterous than a human’s, licks across his weeping entrance, before dipping into him. Those large hot hands now grab and squish his ass cheeks as the demon eats him out. With every moment they touch him, he feels more sensitive, the cold air stinging the expanding flesh.
Izuku whines, desperately trying to roll his hips to encourage the tongue to dig deeper into him. A pleased growl rumbles from the demon, rolling through the human. Izuku, who by this point is well acquainted with the feeling of the demon’s magic, gasps as his insides shift and relax, tingling with the tell-tell signs of magic.
‘Oh’, he thinks, as Katsuki removes his tongue, lining the now soft and ready hole to his engorged cock. Whose size matches his currently massive frame.
It pushes in, faster than Izuku would like, slower than he was expecting from the enraged demon. Katsuki’s dick stretches him, magic convincing his organs that it is meant to be there not them. As his ass sits against the demon’s pubic bone, his stomach swells at the girth currently hidden inside of him.
As always, there is no pain. The stretch is vaguely uncomfortable, but it is quickly drowned out by the itch, the need to fucked into a puddle. The hunger for the demon’s hot cum.
“K-Kacchan, p-please,” Izuku begs, his own tongue lolling out of his mouth, unable to contain it against the growing tide of pleasure.
“Is this what you wanted, slut?” The demon growls, rolling his hips, not quite moving enough for Izuku’s tastes, teasing the human, “Didn’t get enough demon cum so you decided to find the first scaly fucker you find to give you that extra fill?”
The demon leans over Izuku, dwarfing him completely. His skin is like a sauna, warming Izuku’s front as his back is chilled by the icy ground. Katsuki produces enough heat that the snow around them begins to melt. A large hot hand grabs the man’s face, forcing him to stare into the red and white eyes.
“Do I need to chain you to the bed like a dog? So, I can get the ritual ready without worrying about my wayward priest fucking every surface demon who waves a cock in your pretty little face?”
Katsuki punctuates the question with a cruel snap of his hips, and Izuku moans, slick oozing out of his abused hole, chilling the skin below.
“You’d like that wouldn’t you, tied down, fucked out. Spell it so all of my cum stays inside until it's coming out your mouth and nose? Or maybe,” The demon growls, beginning to properly thrust in and out of him, “Maybe you want to just be stuck on my knot forever. Carry you everywhere, so that you are fucked with every step that I take? Have the blacksmith make a little harshness so I don’t have to waste my time holding you close, just tie you to me? That your heaven Deku? Permanently fucked on my massive dick? Fuck,”
Izuku’s eyes roll back, tears freely falling down his cheeks, as the demon dissolves into a series of angry growls and barks, fucking him harder and harsher than he has ever had before. The pleasure is mind-numbing, and Izuku feels a bit like just a breathing cocksleeve in the face of it.
With a howl, Katsuki sinks into him, his already too-large dick swelling at the base, locking them together before dumping buckets of boiling hot cum into his stomach. His stomach groans as it grows, by the time the demon has stopped cumming the human looks very pregnant. Izuku cums one last time at the sight, before completely collapsing to the ground, breathing heavy as the weight in his stomach presses against his lungs.
Letting go of the bruising grip on Izuku’s face, the demon leans down and licks at his salty tears, purring deep in his chest.
“What a good boy, taking all of me in this form,”
Still locked together, the demon cradles him into his arms, and off the cold ground. With minimal effort the demon stands, Izuku safely tucked in his arms, grabbing the long-forgotten basket of berries as well.
“Kacchan, we can’t leave the forest on fire,” Izuku whispers, voice belaying out fucked out he is. With a huff, the flames dissipate, leaving the woods surrounding them scarred by the demonic fire. A new pressure begins to rise in the clearing, but before it reaches its crescendo, Izuku finds himself slipping off to sleep.
Katsuki doesn’t want to let the human out of his grasp, even after his stupid Deku has passed out during their trek home, fragile human body exhausted by the teleportation magic and other activities. The rage that still bubbles and boils in his veins makes trying to return to a normal humanoid form impossible, barely able to shrink his horns enough so he can make it through the doorways.
How dare some lesser demon think that they could tread on Katsuki’s lands, how dare they even consider threatening what belongs to him. The shit had even known Katsuki’s name and still it promised to return, as if that wouldn’t get it a one-way trip to being dusted. Did it think that after all this time Katsuki forgot how to kill demons? When he was a celestial creature that was one of his main jobs. The unwinding of demons and other celestials. It is a known fact about him. It is why he is so feared across the realms and the greater demons let him fuck off on his own business.
They are less than a month out from the darkest night, mere weeks away, where the veil is pulled thin enough for Katsuki to slip through, and the last thing he needs is for Izuku to fuck everything up.
He stomps through the church, heading towards the baths, ignoring the little voice in his head saying that it is more than that. All Katsuki wants is to become a celestial being again. To no longer be bound to the earth. He doesn’t care if it is this human that will get him there, if Izuku breaks or is broken before then, Katsuki will have to start over and wait another year. He tries to ignore the uncomfortable feeling he gets at the thought.
The water begins to run into the large bath with just a mere flick of his wrist, as he sits on the ground, waiting for his knot to go down. He can no longer smell that fucker, which is good. They are safe here in their den, he tells himself, Deku is safe.
Unwarranted, the image of Deku pinned under that greasy fuck invades his mind, and he subconsciously growls, curling more around the slumbering human. He buries his nose deep into sweaty green locks, breathing in the human’s natural scent, untouched by any creature besides Katsuki himself. It is going to stay that way too. It is enough to calm him down, his dick slipping free from the wet heaven between Deku’s legs.
Part of him wants to leave the human bloated as he is, stomach round and taunt with his seed. Deku looks so good like this. He does know that it will come out eventually, easier to deal with now, than waking up in a wet mess...again. Though, seeing the human’s body swollen with his cum, makes him daydream about fucking spawn into Deku. Definitely something to think about after Katsuki is a god.
Instead, he lays Deku against the ground, making sure his head is at a proper angle, magic disappears the scraps of clothing that had survived his earlier rage. Even asleep, the human makes such cute little whines as Katsuki gently presses two fingers into his fucked out hole, wiggling them as he presses down on Deku’s stomach with his other hand, watching with glee at the literal tide of cum that gushes out.
With the human empty, he picks him up, and sits both of them in the tub, cleaning the dirt and mud from his skin. His hands wander to the slightly larger tits and ass he forced onto Deku, gently massaging them, easing the swelling. Katsuki knows he has to be careful about any more body modifications before the ritual. Human bodies are like dough, knead and bother it too much, they become dry and brittle. Everything that he has read about post-ritual, though, makes it seem like Deku’s body will be more like clay, malleable, changing shape to Katsuki’s will. At that point, he could do just about anything he wants to his priest. He will have the power, and Izuku will be less likely to break from their fun.
Once they are clean, and dry, Katsuki heads towards their nest, not bothering with clothing. He is still riled up that he cannot shift into a more normal size of human, instead he stays his towering nine feet, just magicking the bed larger. With a groan, he sinks into the soft sheets with his little human pressed close to his side.
The ritual is only weeks away, and things need to be done carefully from now on. He feels himself slipping off to sleep, face buried in soft green curls.
He cannot lose Deku
The thought is enough to jolt him awake somewhat. Does, does he care specifically about this one fragile little human? Humans are replaceable, a dime a dozen. Deku is far be it the first human he has tried this ritual with.
He is, though, the first human he has lived with this long and the first human that has made it this far. Most are lost the first time he fucks them, or the second or the third. Deku just whines for more as he is stuck on Katsuki’s knot.
And maybe it isn’t just the sex. It is chatting with Deku during the day, listening to the human ask inane questions and finding ridiculous ways of answering them. It is working beside him, tending to the gardens and animals.
Could he continue this path if he fails with Deku? The more he thinks about it, the more he realizes if they fail, Katsuki will be a demon forever. He will never find a human more compatible to him.
He must protect Deku at all costs, now and after they succeed with the ritual.
This vulnerability scares him. Katsuki has spent the past centuries alone or near alone. He doesn’t count the stream of broken humans he has created on his way to Izuku. In fact, there is really only one other creature he can stand, another ex-celestial, but he hasn’t seen that spiky haired fuck in nearly sixty years.
He is used to it by now. Because there was no option before Deku, not really. He could have done what other Fallen had done, immerse himself and enjoy the revelries of hell. Bind himself to some great demon or another god. Katsuki always suffered from an excess of pride, he refused to bend the knee again to an inferior creature. Which had led him to the decision to try to re-ascend himself.
Deku, as a person, has surprised him. Katsuki finds that he does enjoy spending time with the human. The man is funny and smart, not to mention he is very attractive. Which he supposes is a good thing considering that they will be bonded forever after the ritual. That doesn’t mean bad things can’t still happen to him after the ritual. Katsuki needs to keep him safe.
He says nothing to the human, even after he has woken up. Deku is clingy, the situation with the other demon clearly having scared the man. Instead, Katsuki lets it simmer in the back of his mind until several days later.
They are in the kitchen, Katsuki sitting at the table while watching Deku stand over the stove, berries that he gathered from the day in the woods bubbling in a hot syrup. The human hums along to some hymn, the only reason that Katsuki knows that it is a hymn is the vague buzz of energy he gets as he listens.
For the past several hours, they had been lightly chatting as Deku worked on this batch of jam. There are still quite a few left in the container of water the human had them floating in. More than likely, they will be at this again tomorrow night. Normally, Katsuki would have wandered off by now, but, even if the human doesn’t out right say it, it is clear Deku doesn’t want to be alone.
“I am almost out of some spices and pectin, might need to go into town tomorrow and get some more,” Deku mutters to himself, already listing what he will buy out loud.
The harsh tone that escapes surprises even Katsuki. It is clipped and dark. He knows where he is coming from, he just hopes that Deku will understand.
Izuku can only stand and stare at his demon, knowing his surprise is evident on his open face.
“You are not to leave the church grounds,” Kacchan’s voice is steady and firm, as if daring Izuku to disagree with him. The human kind of wants to, though, he isn’t some kind of pet. Right?
Red eyes narrow, clearly catching onto Izuku’s thought process. He stands and moves into Izuku’s personal space, a large hot hand grabbing Izuku’s chin, forcing him to make eye contact,
“I think you forget, I am a demon, and while I am going to be your god, I never said I was going to be a merciful god.” He growls into Izuku’s face, red eyes burning into Izuku’s green.
In his chest, Izuku’s heart beats like a rabbit’s. He knows this, but up until this point, Katsuki hasn’t really done anything truly controlling outside of sex. Tears pool in the corner of his eyes as he nods. Something changes in Katsuki’s face, and Izuku would have missed it if he hadn’t been staring so intently at him. The hand releases his chin but pulls him forwards by the back of his neck, pressing the human’s face into the demon’s chest.
“I cannot risk anything happening to you,” Kacchan whispers, his other hand petting softly through Izuku’s soft hair reverently. “If that demon hadn’t been so weak, we might have been in trouble. If he had set up a barrier, so that I could not hear your prayer. He would have fucked you out of your mind, most demons aren’t as careful as I am.”
A shudder races down Izuku’s back at the thought of it. There have been several times when he has felt overwhelmed by the pleasure that Kacchan gives him, it would be understandable how easy it would be to break on it. It does make him feel a little warm at the thought that the demon has been careful with him.
That the demon sees him as special.
It seems to be the end of it or at least as much emotion as the demon can handle, because Kacchan quickly turns on his heels and leaves the kitchen. Izuku stands awkwardly in the silence left behind. Katsuki has been very careful these past couple days, ever since the other demon showed up.
He knows that he is important to the demon for the ritual, and then finding another priest this year would be impossible. But for some reason he feels like it isn’t just that. Kacchan had stuck with him during the past couple days because Izuku didn’t want to be alone. The demon frequently goes into town to harass the villagers, but he has stayed with Izuku this entire time. And Izuku didn’t even ask him to. There is something else going on, and Izuku is going to find out.
With this in mind, Izuku springs into action. He quickly puts the things away, storing the cooling jam outside in the cold, before following his demon.
The demon is standing in the bedroom, smoke curling from his mouth and hands. Izuku pauses only for a moment. Katsuki won’t hurt him, he knows this, for selfish reasons or otherwise, Katsuki will not hurt him. With a confidence he rarely feels, he folds himself up against the demon, who is quick to wrap his arms around Izuku.
“It is only until I ascend,” Kacchan mummers softly, “After that, you will be safe no matter where you are, because I will always be with you,”
That is new
“What do you mean?” He asks, pulling away from the demon just enough that he can look into the deep red eyes
Kacchan hums, frowning a bit before looking away from Izuku, “From what I remember, a little bit of a God is present in all of its works. You will fall into that category, mine in every sense of the word,”
“You have mentioned that before,” Izuku ponders out loud, a little hesitant that he is about to go too far, “You were a god before?”
“No,” the demon snaps, smoke curling from his mouth, before letting go. Izuku doesn’t step away, instead staying close, basking in the warmth of his demon. He is thankful when Katsuki doesn’t push him away either.
“I was a celestial though, a warrior, a general in the holy armies of your old God, All Might. When he disappeared, he took those he deemed worthy with him, leaving the rest of us to fall into hell for no crime other than we were not his favorites,”
There is so much pain when Katsuki whispers this to him, stretched across an unknowable amount of time. Izuku thinks about his own lesser betrayal, that All Might had been gone for so long, but had said nothing to the humans that still pray to him. It is not the same, not even close. Izuku distantly wonders how many years his demon has spent alone; how hard it must have been.
Kacchan moves to lay on the bed now that he is no longer smoking, and Izuku moves to follow, curling on his side.
“I will never leave you,” Katsuki whispers, voice firm in its conviction, “Whether you like it or not, you will be mine forever,”
As Izuku lays against the demon, he finds that he doesn't mind so much.
Time after that seems to move quickly. Izuku agrees to stay on church grounds, to alleviate the worries of his demon. In return Katsuki often sticks around when normally he wouldn’t, only going to town to grab things that Izuku needs and would normally get himself. Still the ritual hangs over both of them, hovering over even the easiest of conversations.
Katsuki still won’t tell him exactly what will happen, part of Izuku thinks it's because he doesn’t really know either. The other part thinks there must be some element to it that requires Izuku’s naivety.
The eve before the ritual, Katsuki takes him to their nest, kissing him softly and explains that the next 24 hours are going to be a rough one for Izuku. He isn’t going to be able to eat, either food or demon cum. Izuku balks a bit, remembering how horny and desperate he gets without proper sustenance.
To prevent Izuku from mindlessly doing something to mess with the ritual, Katsuki ties him down. Kacchan is careful, every tie is as tight as it needs to be, without hurting him. His wrists are tied together and then against his chest, while his thighs are tied to his ankles. By the end, the only thing that Izuku can move is his neck. Kacchan sleeps curled around him, purring deep in his chest.
When Izuku wakes the day of the ritual, he can feel it in the air. Kacchan has lived with him for almost four months now, growing more powerful every day. All for this. There is a hush in the air, as if the whole world is being held at the edge of a knife. It is something that Izuku has noticed his entire life, this day of darkness always brings such an unnatural stillness.
Even as the sun sits low in the sky, the veil pulls itself thinner with every passing moment. The line between realities growing more brittle the closer to night they go. Kacchan is gone most of the day, only showing up to give Izuku water and to make sure he is still comfortable.
He is not
The itching hunger grows within him, he hadn’t eaten anything, neither food nor demon cum in since yesterday. Instead he is tied to the bed, writhing against the bonds, desperate for Kacchan and unable to find any relief. Part of him is a bit embarrassed, but it is so buried under the lust and hunger.
It gets worse as the day goes on; he is so wet that he must have flooded the bed by now. When Kacchan finally enters the room, dressed in an intricate robe, Izuku almost weeps for joy at just the sight of him. His demon says nothing, just picks up him in his arms, keeping him bound, and heads to the parish hall.
Izuku can barely recognize his place of worship.
The church has been stripped barren. The pews, the alter, the icons, everything has been removed. In the newly empty space, sigils in red, gold, and black have been painted on the floors and walls, some even curling onto the ceiling. In fact, the only area not covered in the paint is a circle put in the middle of everything.
Katsuki carries him to the center, picking out an unseen path and carefully setting Izuku down in the center of it all. Bound as he is, all Izuku can do is stare up at the ceiling and at Kacchan as he passes over him. He shudders as the demon begins to paint something on his skin, whatever substance is cold against Izuku’s fevered skin. Little moans escape him, his body so desperate for touch. Above him Kacchan laughs softly at him, hushing him when his whines get too loud.
Once finished, Katsuki sits back, so that Izuku can only see the tip of his face, impassive as he waits for the moment to begin.
Twilight bathes the church in an unearthly glow, and Izuku gasps at the parting of the veil around him. Kacchan is saying something, but the words hurt to listen to. A tongue not meant for human ears, still he keeps his focus on Kacchan.
A crunching cracking noise near startles Izuku out of the daze he has been slipping into, so focused on Kacchan’s voice. It sounds like the wood of the church is splitting, peeling away from itself. Above the blonde’s head, Izuku can see starlight.
Something that Kacchan says sounds like a question, and words are forced from Izuku’s mouth, in the same unknowable tongue that his God is speaking in. But it isn’t so unknowable anymore. Suddenly, even though the words themselves are lost on Izuku, the meaning sinks into his mind.
Kacchan had asked if he was willing to accept his new God, allow him to ascend through Izuku and Izuku had answered in the affirmative. While the language and the words themselves are forced, the feelings behind them are not. Izuku wants this for Katsuki, wants him to succeed.
Words like little knives are spoken again, Kacchan waits for his answer. What will Izuku give in offering to his new God?
Izuku knows in his heart of hearts, knows without a doubt his answer, even as it is forced from his lips by the ritual magic. He loves Katsuki, loves the angry possessive demon that makes him do crazy things, and does crazy things to him. More than anything, he wants Katsuki to win, and wants his new God to emerge more powerful than any that walk the planes of existence.
-My body, my soul, my heart, my mind, my everything-
Around them, the church explodes and freezes. Scraps of wood hang in midair, the only untouched place is the circle where Izuku lays and Kacchan kneels.
The blond is panting heavily, Izuku can feel him weakening, using all of his strength to keep the ritual going. Izuku is still bound, so he cannot reach out to him, instead he prays. He reaches, blindly, for the first one that he can think of.
My lord, bless the traveler on this longest night, bring them home safely, let their weary head find the strength to continue on. Let your will be done, and grow strong in my heart
Blood red eyes snap to him, and for a wild moment, Izuku thinks he has done the wrong thing. However, before he can even think of a way to apologize, Katsuki is sliding over his prone form, and kissing him deeply, before rearing back, ripping Izuku’s beating heart from his chest
Katsuki opens his eyes in the twilight realm of his beginnings. Gold light shines everywhere showing the damage and the rot that has been allowed to accumulate with the lack of a God in the seat of All Might. It has been far too long since he laid his eyes on this place, though, it always seemed grander in his memories, larger.
He feels like there should be dust covering every surface, but of course there isn’t. The celestial plane doesn’t exist in the same way that earth or hell do. Golden rooms pass him by as he heads deeper into the halls of an absent God.
The throne of All Might is just as wondrous and terrible to behold as it was when it was occupied. There is a nameless awe to the structure, unknowable to mortal minds. Along the arches of the throne room are pedestals, once filled with the great treasures of the celestial race, now empty of what All Might considered precious. In their place are other things that had not been here the last time Katsuki was.
He knows these items are what the few others to walk this path have brought to tie their godhood to. They are an off color, the new celestial glow not the same as the original, and Katsuki doesn’t know if that is a bad thing or not. The other treasures are items, like a lute or a sword.
His will stand out amongst them.
On an empty pedestal, near the spot he used to stand to wait for his God’s orders, he places Deku’s still beating heart. It drips gore for only a moment before it too begins to glow in heavenly light, the red rivulets turning gold.
Katsuki does not spare the grand hall another glance, instead closing his eyes and returning to earth, wreathed in celestial light. It feels different, being on earth as a god. For a demon, every breath is pain. The earth wasn’t made for them, and while they exist on the plane, it isn’t without its costs. Without a proper food source, the strain will eventually take its toll, sending the demon back to hell to recuperate. As a god, each breath is just that, a breath. A simple action. There is no pain nor relief in it. In fact, Katsuki isn’t sure he even needs to breathe.
The wreckage of the church shudders around him, as he kneels next to Deku, who only by Katsuki’s will is still breathing. With a pull of new divine powers, he spins a new heart, dark red with hints of gold and black, Katsuki’s heart, and places it in the safety of the man’s chest.
Deku’s stares at him, eyes wide with adoration and love, and it feeds Katsuki. Sex and violence fed him as a demon, and they would still feed him now. He is not some “pure” God, his time as a demon as seen to that. Katsuki is a God of Spring, of change, of ruts and sex, of birth. He is a promise of a storm, the terror of the floods and the relief from the droughts. His territory stretches across Musutafu like he expected but much farther as well, it would take a human four day’s travel to get from one end to another.
And it is all because of Deku.
Around them the church reforms, and Katsuki can feel himself in it. This hallowed ground, stolen from the absentee god, and re-christened in Katsuki’s name. It is almost the same, but the paint is fresh, the wood shines, and Katsuki is here. Even when he is not physically in the church, he exists in this space.
The energy from the ritual begins to dissipate, and Katsuki half collapses above Deku, panting from the strain of changing forms again. Said human reaches up, touching Katsuki’s cheek with a reverent shudder.
“Kacchan?” Deku asks, his voice soft, but the question sends a thrill of bright energy rushing through Katsuki’s spine.
He can also feel a bit of himself in Deku as well. In the soft beating of his new heart. Katsuki leans down, kissing along the edge of the green haired man’s jaw. Said human moans softly at the touch, so hungry, still bound to Katsuki the same way he had been when Katsuki was a demon.
The very thought sends a jolt through him, was a demon. No longer a demon.
Deku lets out a whiney, “Kacchan,” when the god bites a little too hard against the soft flesh. Another roll of pleasure sings through his veins at the sound of his nickname spoken by his priest.
“Say my name,”
The human complies again, and Katsuki grins. It is manic, nothing like the soft looking icons that once lined the parish hall. He hadn’t been lying when he said that he wasn’t going to be a merciful god. Hearing his name spoken like that, it fills him with such strength and joy.
Unable to stall any longer, he swoops down, capturing Deku’s lips. Deku whines deep in his throat, enjoying the attention, but his hunger is apparent. Using the strength from Deku’s little pleas, he pushes back onto his knees, banishing the heavy robe he had been wearing, unraveling its existence with a hush.
“Poor little slut, you hungry?” He purrs, grabbing the ties that still bind the human across the chest, and pulls Deku forwards, so that his face is pressed against Katsuki’s exposed crotch. Deku moans, his little pink tongue darting out to give his God’s hardening length little kitten licks.
Knowing that Deku cannot move himself presently, Katsuki is gracious enough to lift Deku back by his hair with one hand, while rubbing the tip of his cock across the human’s cheeks with the other. Deku whines, desperately chasing after the dick with this tongue.
Finally, the God gives him what he wants, shoving the dick into the waiting pink mouth roughly. With the tip firmly lodged in his throat, all the noises Deku tries to make are effectively silenced, all any of these attempts do is gently vibrate Katsuki’s dick. Katsuki knows how his slut likes it.
Moving both hands into the nest of soft green hair, he begins to fuck Deku’s throat. Pre-cum and spit smoothing the motions. Deku’s tongue does what it can, pressed against the bottom of his mouth. It feels so good. Better than any of the times they had done this before.
Neither last very long. Katsuki hisses as his knot forms behind Deku’s teeth, finally cumming. Deku sobs with relief as the cum hits his stomach, feeling full for the first time in a day, his little cock bobbing as he makes a mess all over himself.
They stay there for several long minutes, as Katsuki continues to pump the human’s guts full of his seed. Eventually, Deku pops off from his knot with a wet noise, his freckled face flushed with a little dazed smile on his lips. He still is leaning against Katsuki’s thighs, unable to move himself with the binds.
“You enjoy your dinner?” Katsuki asks with a laugh, and the nerd, of course, nods. With a little push, the nerd is overbalanced and falls flat on his back with a grunt. “Ready for seconds?”
“Kacchaan,” Deku whines, and Katsuki can see the way his muscles bulge against the ties, trying to move closer to his god.
With a snap of his fingers, the rope that has been keeping Deku from moving falls away. Thankfully magic had kept it from pressing to hard against the skin, so all that is left is a fast fading pink line. The human relaxes against the floor, waiting to see what his God does next.
“Such a messy whore,” He mutters to himself, running a clawed finger through the mess on Deku’s abdomen before plopping it into his mouth, all the while Deku watches with eyes black with arousal. It is easy to pull another moan from the human, as soon as Katsuki’s tongue touches his skin.
No longer bound, Deku’s hands are quick to tangle in Katsuki’s hair, holding on for dear life as the god licks, bites and pinches up and down the human’s chest. This close, Katsuki can hear the heavy beats of the heart in Deku’s chest, Katsuki’s heart. It sends such a bolt of arousal through him that he can barely stand it.
Growling, Katsuki pulls back, large hands grabbing and throwing pale thighs over his shoulder as he gets into position. Deku has flooded the area under his sex, his opening soft and waiting for Katsuki’s thick cock.
“Kacchan, pleas-” Deku begins to beg, but is cut off by Katsuki thrusting in. As always, Deku’s insides welcome Katsuki, gripping him tightly as he tries to pull out, not wanting him to leave. Katsuki is happy to oblige, pushing deeper with every thrust, stirring up the human’s insides with a grunt.
The sudden pain in Katsuki’s back almost rivals the pleasure from his dick, so much that he stills his hips. Beneath him, Deku watches him with wide green eyes. There is the sound of ripping, and Katsuki growls as something pushes its way from his back. Just as it arrived, the pain is suddenly gone, leaving behind a heavy but familiar feeling.
Tears prickle at the edges of his eyes, but Katsuki refuses to let them fall. He stretches muscles he hasn’t had in millennia. Wings spun from light arch around them. He has kept his horns and tail from his time as a demon, but his wings have been returned to him.
“Beautiful,” Deku whispers, capturing Katsuki’s attention once again.
“Speak for yourself,” The God says with a victorious grin.
With a snap of his hips, Katsuki begins thrusting back into the tight wet heat that is Deku’s insides. Every time he pulls out, his knot catches on the human’s rim just a bit more. Even with his belly full, Deku is insatiable, howling and whining like a bitch in heat, begging for Katsuki’s knot.
Who was he to deny his priest?
Grunting, he thrusts in as his knot swells, locking them together. In tandem they moan, Deku cumming again at the feeling of his guts being pumped full of his God’s thick seed. Pressing down, nearly folding the human in half, Katsuki captures swollen pink lips into another deep kiss.
“I love you Kacchan,” His priest whispers sleepily, as they break apart. Katsuki cards one of his clawed hands through silky green locks.
“Love you too, nerd,”
It is different, leading a service the following Sunday. Before, even before Katsuki came to stay, the words that he said felt rote. Things to be said, not because Izuku believed in them, but because they must be said. Because Izuku has been told they must be said. Now, with every word he says, he can feel the buzz, feel his connection to Katsuki grow even stronger. Izuku knows now that even the prayers from the congregation feed the blond. Anyone who worships in this space will feed him.
The god sits in the front pew, as he always does, red eyes watching him. The congregation does seem to notice, but these days Katsuki almost always has his non-human extremities out. Black dual set of horns, thick wiggling tail and large golden wings, every time he sees his God like this, his breath catches in his throat.
Izuku doesn’t know why it feels so risqué, to pray to a being that is literally right in front of him. Perhaps because it feels so good? His new heart beats softly in his chest, as he locks eyes with his God, and declares his love for him, the voices of the congregation rising and joining with his.
Kacchan smirks, and makes his way to the altar, and Izuku cannot stop himself from smiling in return.