Prologue: The Yellow Demon's Contract Renewal
A vast city thrummed with the energy of reconstruction.
There, a triumphant parade was unfolding to welcome the troops who had returned victorious over the invaders.
Waaaaaah~~~!!
"Your Majesty!"
"Kyaa! The Queen looked at me!"
At that moment a woman appeared, her lustrous sapphire hair cascading like waves as she led a massive pure-white reindeer crowned with enormous antlers.
The sight of that beautiful woman—radiating both strength and elegance—mounted atop the great reindeer at the head of the procession was more than enough to draw every eye.
Clad in gold-leafed armor, she accepted the people's cheers while the victorious soldiers followed behind her with proud, measured strides.
Yet not everyone received such acclaim.
Among them walked a presence that was unmistakably alien.
Thud— thud— thud—
A towering frame nearly three meters tall. A colossal greatsword resting against one shoulder, large enough that a single swing could cleave through dozens. Bone armor. A skull helm. Black horns thrusting from the forehead. Massive bone wings wreathed in flame, and a thick black tail. Skin the color of molten lava—an existence clearly not human.
"That's a real Yellow Demon…"
"Insane… Even the Demon Kings don't mess with the Yellow Demons lightly. How the hell…?"
Men who had only recently arrived in the city stared at the Yellow Demon in open bewilderment. In the Demon Realm, where the strong reigned supreme, the Yellow Demons were infamous as pure combat fanatics. Watching one stroll casually among humans was no different from watching a savage beast wander the streets.
"You lot must be from somewhere else, huh?"
"We immigrated recently, but… you all seem used to this?"
"We were tense at first too, but after seeing her around long enough you get used to it. She doesn't cause any trouble."
A local resident chuckled as if it were nothing special.
"How is a Yellow Demon that well-behaved?"
"Apparently the black mage who's been with Her Majesty since she started restoring this country made a contract with her."
"A contract? Yellow Demons can't make ordinary contracts…"
Most demons sealed pacts through some form of exchange. Yellow Demons, however, were battle-obsessed warriors who would only obey another after being defeated in combat. Win, and you could command them without any further conditions. Lose, and you forfeited your life. Because they insisted on one-on-one duels as the terms of any contract, fewer than five people in the entire history of this world had ever successfully bound a Yellow Demon.
"Just what kind of black mage is that?"
"Where is he, then?"
"Hmm… Usually he's somewhere near Her Majesty, but I don't see him today. He's less a sinister black mage and more like a timid little rabbit, so he's normally easy to spot."
The resident shrugged, muttered that the mage was probably resting somewhere, and turned his attention back to the parade.
"A timid rabbit?"
"A black mage?"
The men searched for the black mage who had contracted a Yellow Demon, yet no one managed to find him before the parade ended.
In that moment, an unidentified liquid dripped steadily along the path the Yellow Demon had walked.
But the liquid was trampled under the boots of the soldiers following behind and vanished without a trace.
Inside a palace where luxury and a dark atmosphere coexisted for 'certain reasons,' the Yellow Demon strode toward a particular destination.
Ordinarily a violent Yellow Demon would never be allowed to roam freely through a royal palace frequented by royalty and high nobles. Yet because the black mage who held her contract shared a 'special' relationship with the Queen, a private chamber for the Yellow Demon existed within the palace itself.
"Hnnngh…! Ahhnnn…!"
Once free of prying eyes, the Yellow Demon braced herself against the wall, both legs trembling violently. For a Yellow Demon—who could remain standing even with her legs shredded—to shake like this was an event that would have stunned anyone who witnessed it.
She dismissed the armor forged from the bones of an ancient dragon she had hunted herself. The moment it vanished, wild black hair and a face previously hidden by the skull helm were revealed.
A face that carried the strong, bold air of a female warrior yet possessed delicate lines that emphasized her femininity. Overall she was a beauty, yet stood nearly three meters tall. Unlike humans, the whites of her eyes were black, and her pupils blazed like living flames—scarlet proof that she was something other than human.
Schlick-schlick-schlick-schlick-schlick-schlick—
"Haaah! Hah! Sis! Siiis!"
"Khhnn…! Y-You little… stop… it… there…! Hnnngh♡"
And there, wrapped around the Yellow Demon's lean, flexible, powerfully toned body with his legs and gripping her flanks, was a boy.
Pure white hair and matching white eyes. At a glance he looked cute and delicate, yet his frame held surprisingly well-trained muscle. Barely over 150 cm, the boy was currently thrusting his hips like a monkey in heat between the Yellow Demon's thighs—twice his size.
Schlick! Schlick! Gulp— gulp—
Ahh♡ Every time his cock pounds me, the cum inside my womb sloshes around…♡
The Yellow Demon woman's every hole had been trained without a single day's rest by the boy. Each time his cock slammed against her cervix, pleasure shot through her and her legs threatened to give out completely.
"I-I'm gonna cum! Squeeze me with that muscular pussy!"
"Hnnn♡ S-Stop♡ My womb♡ is already full♡"
Schlick-schlick-schlick-schlick~~
At first she had desperately tried to resist the boy's cock, but soon her voice softened into something sweet and her rigid expression melted into that of a female in heat.
"Aaaaaaah~~~~!"
"Kiiighhhhh~~~~♡"
Blergh— blurrrgh— bloop—
The boy buried himself to the hilt and came. The Yellow Demon woman could not withstand the pleasure of cum battering her cervix and collapsed onto the floor.
"Haa… haa… haaa…"
"Hah… hah… hnn…"
Boy and Yellow Demon woman shared the afterglow of pleasure, exchanging body heat.
Schluuurp—
"Hnnngh♡"
Once he had savored the aftershocks enough, the boy pulled his 'massive' cock free of her pussy. It was not merely large relative to his frame—it was a size that transcended species. So thick that even both of the boy's hands could not fully encircle it, and when held upright it reached all the way to his collarbone. Unlike a normal human cock, it lacked a mushroom-shaped glans; instead it was a long, solid shaft with a slightly recessed urethral groove, resembling a horse's cock. Tiny nubs jutted randomly along the shaft, designed to force pleasure into any woman it entered.
Then the boy's cock shrank to roughly half its size. With agile movements he lunged toward the face of the Yellow Demon woman still slumped on the floor.
Schloop!
"Mmph!? Mmmphhh!"
He shoved his cock into her mouth and began rocking his hips. Still seated, the Yellow Demon woman's upper body swayed; she could not endure the boy's cock and toppled backward.
"Sis, you've gotten pretty good with your tongue. But stabbing the back of your throat feels best, right?"
From above her face the boy slammed his hips down hard, driving his cock deep into her throat.
"Hnnnph♡ Schluurp♡ Schlick♡ Chuuurp♡"
Startled at first, the Yellow Demon woman soon moved her tongue exactly as she had been trained—sucking and licking while her throat was pierced. Even as she suffered the pleasure, her face twisted into something vulgar as she enjoyed it. She had reached the point where every single one of the boy's actions brought her pleasure.
"Hnnngh! Sis! Harder! Suck harder!"
"Schluuurp~♡ Schloop♡ Poooh♡"
"B-Best ever, Sis! My hips won't stop! Again! I'm gonna cum again! Gonna fill Sis's mouth-pussy!!"
The Yellow Demon woman's mouth-pussy obeyed the boy's every command. He pounded his cock into her face hard enough to slap her with his hips.
Blurrrgh! Blergh! Blooorgh!
"Aaaaaaaah~~~!"
"Nnguuuuuuh~~~♡"
Without warning he buried himself to the root and came. Cum shot directly down her throat. Even though the Yellow Demon woman possessed resistance high enough to use fire—no, even lava—as a shower, her entire throat burned as if scalded.
The boy treated her like a mere tool for his own climax.
It's this humiliating, this degrading… so why doesn't it feel bad…?
No matter how much rage she tried to build, every time the boy's cock pierced one of her holes the accumulated fury vanished in an instant. What remained was a strange happiness and fullness she had never known before in her life.
"Hnnngh~~!"
Schluuurp!
"Cough! Cough!"
When the boy finally pulled free, the Yellow Demon woman coughed up the cum she had failed to swallow.
"Haa♡ Hah♡ Hnnn♡ Haaah♡"
Tasting and smelling the thick load that still filled her throat and mouth, she let out happy moans while her massive body rose and fell.
But the boy had no intention of stopping there.
"Come to think of it, the contract ends today, right? Let's 'renew' it."
"Nngh…♡"
Just as the residents had discussed during the parade, a contract with a Yellow Demon was nothing like an ordinary demon pact. It required a one-on-one duel free of outside interference.
"I, Jin Resili Caisent, challenge Bealderin Regul Board to a duel for the renewal of our contract."
The boy who named himself Jin Resili Caisent poured mana into the contract sealed within his body and requested the renewal duel.
Ordinarily she should have possessed the right to refuse, yet for her—and for every Yellow Demon—no such option existed. Especially not when it was a renewal. Refusing a renewal challenge was no different from fleeing like a coward.
"I… I… Bealderin Regul Board… accept… Jin Resili Caisent's… renewal challenge…"
The moment she accepted, the two of them were transported into a void dimension—a spherical space the size of a sports field. Immediately afterward they were teleported a suitable distance apart to ensure the duel’s fairness.
The only ways to leave this void dimension were for the challenger to die or for the Yellow Demon to declare defeat.
The teleportation finished and the duel began—yet…
"Heheheh."
"……"
The boy, Kaisent, approached her with a sly grin.
"Bealderin-siiis~"
He closed the distance while speaking in a coaxing, spoiled tone.
Calm down. Calm down. I can't keep being dragged around by this brat. This time for sure…!
Bealderin forced the pleasure down and steeled her heart.
One swing. Just one swing and it's over.
The boy believed she could no longer resist; he was walking toward her completely unguarded, without even a defensive spell. A single strike from her hand or foot would crush even a trained warrior—armor and all—into instant death. In other words, one attack would turn this boy, who could not even withstand the force of her index finger, into a bloody pulp.
She hardened her resolve and prepared to strike—only for the image of the boy lying dead to flash through her mind. Her heart wavered and hesitation bloomed.
"Ei~"
Seizing that hesitation, the boy slid smoothly behind her.
Schluuurp—
"Ohoooh~~~♡"
Kaisent spread her firm ass with both hands, buried his face between the cheeks, and began licking her anus with his tongue. As a human-dragon hybrid, Kaisent possessed a tongue longer than any ordinary human's. When he thrust that tongue deep into her ass, Bealderin's eyes nearly rolled back and she rose onto her tiptoes without realizing it.
"Sis is still weak in the ass, huh. Strong big sisters always have weak asses, don't they?"
"Th-That's not—♡ Hnnngh♡ Don't… suck… my ass… like that…!"
Kaisent gripped her hips tightly so she could not escape and focused his assault on the inside of her anus.
Schlick— schluuurp— schloop!
His tongue, buried deep, swept along the floor of her rectum like a snake before suddenly thrusting diagonally upward, stretching the walls.
"Kiiighhhh~~♡ Ohoooh♡ Oh♡ Ooh♡ Nnghhh♡"
Every time Kaisent's tongue moved, her sphincter clenched and twitched, trying to squeeze the invading tongue. Kaisent only adjusted the pressure, swirling his tongue in slow circles to loosen that tightly sealed ring. Each time, Bealderin's tongue lolled, her eyes rolled back and returned, and she sank deeper into pleasure.
I can feel Sis's sphincter wriggling.
Kaisent took satisfaction in the way the flesh protruding around her sphincter twitched against his tongue and eyes. Tasting the bitter intestinal fluids seeping from her walls, his gaze shifted into that of a mischievous child about to play a wicked prank.
Just before Bealderin reached climax, Kaisent silently cast a silent enlargement spell on his own tongue.
Bloop!
"Kyaaaang!?"
His tongue suddenly ballooned, forcing her anus open with a wet creak. In the next instant Kaisent sharpened the tip of his tongue, pressed his lips flush against her sphincter, and thrust the stiffened tongue straight up.
Schliiick!
"Kyahooooong!!"
When Kaisent's tongue stabbed the ceiling of the wall where her intestine curved into the S-colon, Bealderin unleashed a bestial cry as her eyes rolled completely white from the pleasure.
Thud—
The moment her S-colon was attacked she climaxed; her knees buckled and her upper body collapsed. Because she stood nearly three meters tall, Kaisent could still freely fondle her ass even while standing.
"Hehe. Sis is already presenting her ass on her own. Good girl, good girl."
"Haaah♡ Hah♡ Hiih♡ Hiiit♡"
When Kaisent gently stroked the raised hips of the Yellow Demon woman as if praising a pet, the aftershocks of climax still lingering, she twitched and whimpered. Multiple orgasms had left her skin so hypersensitive that its natural defenses had plummeted.
Yet their one-on-one duel had only just begun.
Without chanting a single word, Kaisent pressed his already enlarged cock against Bealderin's anus and pushed.
"Hnnngh♡"
The hot, hard sensation of his cock against her ass.
Schlick— schzzzzz—
Kaisent deliberately forced his cock into Bealderin's anus with agonizing slowness. With every inch that entered, her wrinkled sphincter was pushed inward.
"Ooooooh…♡"
As the cock that had already reshaped her anus slowly claimed her, Bealderin let out a sound that was half sob, half pleasured moan.
Slap!
"Hihooooooh♡"
After the slow insertion he suddenly slammed his hips forward, burying himself to the root.
Schloop— schlick— schlick-schlick-schlick
Already glistening with intestinal fluids, her ass had become a hole perfectly suited for a cock to slide in and out of.
"Nngooh♡ Ohoh♡ Hkit♡ Kyahaang♡ Oh♡ Oh♡ Ooooooh~~♡"
When he had used her pussy she had somehow managed to endure, but the moment her ass was conquered she began squealing like a sow in heat. Whether it had always been her weak point or whether Kaisent's focused training had made it so, Bealderin could offer no resistance whatsoever. She simply took the one-sided assault while Kaisent gripped her hips and pounded her.
"My cock feels good, doesn't it, Sis? Swear it again—swear you'll be my personal shit-hole pussy! Swear on your true name that you'll be my ass-slave!"
"Ohoooh♡ Kyahang♡ Kyahit♡ Ang♡ Ah, ah, aaang♡ Aghnn♡"
Kaisent's cock demanded her defeat. The Yellow Demon instinct that hated losing still sealed the declaration of surrender behind her lips—
"Say it! Say it! On your true name! Declare that you lost to my cock again!"
"Hngoooh♡ Oh♡ Ooh♡ Oh♡ S-Stop♡ Aoooh♡"
Schlick-schlick-schlick-schlick-schlick
Every time Kaisent's cock—enlarged to match Bealderin's massive frame—stabbed into her ass, her belly swelled and receded. With her shit-hole completely dominated by the cock of a boy smaller and weaker than herself, Bealderin was forced to endure the endless lust of a young male who had already tasted what a female was, without a single second of rest, until she finally declared defeat on her true name.