In the far eastern parts of the kingdom lie the backwater province of Nivoy. It is a rural place, its fields and cattle tended to by more or less hardworking peasants and its government overseen by baron Vern of Nivoy.
Despite the modest living conditions, life was good for the most part, more so for the nobleman and his lovely wife than the serfs, of course. Until today.
For today, their second son was dying. It wasn't an unusual happenstance. Infants were fragile creatures and even a common cold could kill one.

The nobleman's mansion was situated on top of a hill. Unlike the luxurious homes built by nobles closer to the capital, it bore the distinctive frugal and defensible look common in the outer provinces. It was a construction of gray stone and red brick. As if trying to match the tragedy unfolding inside, the weather outside was harsh, with strong rain and the occasional thunderbolt lighting up the night sky.
The couple tending to their child in the bedroom was in a dire mood and the servants were gone, having been sent off to fetch herbs in the downpour. Baron Vern could only watch as his wife hunched over the cradle and did her best to keep the child alive. “The fever still isn't coming down.” she spoke miserably.
They already tried everything they could think of – herbal brews, prayer, goat milk, talismans.
Vern held her shoulder comfortingly “Ilena, we've done everything we could. From now on, it's entirely up to him.”
It wasn't just his child that the baron was worried about. It was a terrible affair, but he could take it. His wife, however, he wasn't so sure about. She was always too emotional for her own good, even if she did her best to hide it under a thick layer of proper manners. Between the sorrow and the difficult childbirth she went through recently, he feared for her health. Losing a son was a painful enough prospect without having to worry about losing Ilena too.
“There must be something else we can do. If only we had a doctor, they would know.”
Vern was sure a trained medical practitioner would be of great help, but the King's doctors, magicians and clerics were far from here. In the provinces, people were left to fend for themselves.

They observed the infant in silence, listening to its weak breath. Ilena let out tears and an occasional sob. This went on until a hiss brought them out of their stupor. A green snake made its way into the room through the window.
The baron moved to get rid of it when its eyes flashed red and it spoke, hisses puncturing every word “Worried about the youngling, are you~?”
“It speaks!” yelled out Ilena. “What devilry is this?”
“I am no devil~” hissed the reptile menacingly “I am a demon. Not one of those fools~.”
“We have nothing for you monster.” spoke Vern firmly “Or are you just here to relish our misery?”
Its forked tongue lashed out once, as if tasting it “Misery~. Sorrow~. Tasty, expensive. Not what I want. The youngling, I can save it. Heal it, strengthen it~. I will do it for your souls~.”
It drew out the last word, not even bothering to hide how it coveted it.
It didn't take much to convince Ilena “You can save him? Really?”
Vern, however “Darling, it's a demon. They can't be trusted. And if the paladins find out...”
“If the paladins and priests are too far to save my child they they are too far to tell me what to do too! If you can really save my son, I'll give you your tribute, but leave my husband out of this.”
Vern knew that making deals with demons was dumb. Still, Ilena wasn't thinking straight and bit the bait too hard to let go. He couldn't let her damn herself alone “No, Ilena. If you are going to do this, then I must too.”

She was about to protest, but these words were enough “Then it is settled~.” And with that final sentence, the snake left.
The two of them looked to their child and, sure enough, his condition improved instantly. They gathered around the cradle and observed as color returned to his face and breath steadied itself.
“It worked!” Vern said, relieved that the demon fulfilled its end of the bargain and overjoyed at his son's safety “Ilena, it worked!” he almost shouted and threw his arm around Ilena's waist.
“Oh, it did. It worked perfectly.” she said. But when her eyes turned from her son to her husband, they glowed with a red light.
And then Vern knew things were about to get complicated. “I was told the sensations of a human body were good, but... mmm,” she half-moaned and pulled herself closer into him “this is quite something.”
He tried to disentangle himself from Ilena's body, but she easily overpowered him in a display of unholy strength and pushed him towards their four-poster bed. He could only watch as his wife made her way to him. Her face was as gentle as ever, but the expression on it was predatory, completely unlike her usual self.
“Demon! What did you do to her?”
“I'm just borrowing her for some fun. You swore your souls to me, remember. Doing so is well within my right.”

At that, the gentle light of the candles intensified and gained a red sheen. Under the enhanced light, it was obvious that it wasn't just his son that grew stronger, Ilena rapidly recovered too. Her frail brown hair regained its chocolate luster, straightened itself and softened, the worry lines on her face disappeared, leaving only her usual unmarred skin. She even went past simple recovery and grew an inch taller while her sickly, willowy figure regained the healthy, slim form he remembered. Only the marks of dried tears remained of her previous sorry state. The stress of her second pregnancy seemingly added a decade to her appearance, but the years were now wiped clean, making her look  twenty again.
She approached with quick, deliberate steps and Vern tried to scurry away in terror, but she was upon him too soon.
Her hands held his down on the bed with an iron grip and her face closed upon his in an instant, her lips connecting in a kiss driven by lust and hunger. She forcefully stuck her tongue into his mouth and sucked on it. She kept kissing him, sucking on his lips and grinding their bodies together until the futility of resisting her finally made it into his head.
Then she started licking his face “So good,” she half moaned-half spoke “Servant,” she started speaking between licks and sharp sounds of pleasure “my name is Xila. Mmm...” she paused again to savor the taste. ”Succubus of the seventh order and you two are mine.”

She kept forcefully dragging her tongue over his cheeks and forehead and even slowed down to a more delicate pace to taste his blue eyes and light brown hair before moving down and carelessly tearing his clothes apart.
It wasn't long until she had a firm grip on his erect manhood. “Mortal cock...” she spoke, as if mesmerized by its majesty “but this won't do.” His wife's free hand glowed red with the power of a gathering spell and Vern's fears flared up again “What are you doing?”
The answer came in the form of a burning pain in his crotch that quickly spread to the rest of his body as his body hair burned away, leaving clean skin that was much more to Xila's liking.
Vern screamed in pain, but it was short lived and quickly replaced by pleasure and the familiar sight of Ilena's mouth wrapped around his shaft.
But while his wife was servile and loving, Xila was hungry and violent. She sucked, licked and rubbed it against both the inside and outside of her cheeks, moaning wildly as she tasted and felt it. What she lacked in technique, she more than made up in sheer power. Her ministrations were incredibly intense, even painful at times, but the pleasure easily overshadowed the discomfort.
She spoke to herself, but most of it ended up muffled by the dick in her mouth and he could only make out random words “So good...cock... suck... best... deeper... cum... mortal... want... ”. 
When she shoved the rod down her throat and sucked with all her might, Vern could only gasp in pleasure and reflexively entangle his fingers into her fluffy hair. Normally, he would stroke it and praise her but now, he desperately pulled her head into his crotch. He only lasted for a few seconds before thick ropes of cum shot out of him and into Ilena.
With another gasp, he helplessly thrust his hips forward with each burst of cum. She took the first two straight down her throat before pulling the tip back into her mouth, effortlessly ignoring his grip, and letting him unload onto her tongue. Xila wanted to taste it.
Even after he was wrung dry, she still enjoyed the cum in her mouth, moving it around and across her tongue repeatedly before swallowing. “Mortal cum. Amazing. I feel like I could eat this all day.”

In her desire to drink more semen, she turned back to the source only to find it spent. “Servant!” she addressed “I didn't give you permission to rest! Give me more!”.
“Ilena never sucked it out that hard. I'm all out.”
Her grip on the cock tightened painfully “UNACCEPTABLE! If you are too tired to give me more, I'll just force it out!”
The red glow in her eyes intensified and demonic power coursed through Vern, returning his erection to full power in an instant. The demoness greedily gave her beloved cock a few thorough licks before shoving it back down her throat, this time burying her face completely into his crotch and rubbing her cheeks against Vern's skin as she sucked, savoring the feeling of mortal skin against her cheeks.
She kept her efforts up, only taking the cock out of her throat and into her mouth when she had to breathe. It wasn't long until the second orgasm came and Vern again found himself thrusting his hips wildly. This time, however, a truly inhuman amount of semen flowed out of his tip. Xila greedily passed it over Ilena's tongue and swallowed it with big, loud gulps even as she put more power into her spell to get him ready for the next round.

She refilled him and wrung him dry several times before her thirst was sated. It was a testament to her desire that none of the precious liquid was wasted, leaving her face and dress unstained. 
While her thirst for semen may have been quenched, her thirst for pleasure was not. Quite the opposite. Under the dress she wore, Ilena's pussy was utterly soaked and just aching for dick.
Xila gave the tip a few more affectionate licks before moving on. The dress had to come off first. It was a modest article of clothing, made for everyday use and did little to show off Ilena's figure. Xila tried to take it off at first, but quickly grew impatient and tore it apart before throwing it away.
Now that his wife was free from the covering, Vern could see the full extent of her recovery. She was as healthy as he's ever seen her and then some.
Her breasts were always one of her prettiest features and pregnancy only made them bigger. They grew into nice handfuls. Xila did nothing to alter their size, but tightened them into firm, gravity defying spheres. Her skin, which was until recently a sickly pale went back to its original color and softness which this only served to accentuate her thin waistline, flat belly and quite literally childbearing hips. Her legs were always long and thin, as befitting a highborn lady, but Xila gave them a bit of muscle tone. Her vagina was smooth and utterly soaked. Droplets of her juices were steadily making their way down her inner thighs and her breasts were in a similar state, a drop of motherly milk gathering at each pink nipple. 
She mounted him quickly, wrapping those long legs of hers around his sides and squeezed firmly.

Another wave of demonic power brought Vern to full hardness and Xila immediately grabbed his dick and eagerly squeezed the tip between Ilena's eager lips.
“AAAH!” she moaned and pushed downwards, taking in more of its length. “BY THE NINE HELLS!” she screamed in pure ecstasy as the cock moved further into her. She filled herself and then picked up the pace, screaming and moaning as she pleasured herself. She rode Vern hard, violently slamming her hips into his. 
Vern, supported by the stream of demonic magic, could just barely keep up with her strength and pace, but was more than rewarded for it by the sight of his wife feverishly enjoying his cock, her body illuminated by the red candles and occasionally bathed in white light from the lightning flashes outside. Her long, soft hair was thrown randomly around her as she thrust herself upwards and her ribs poked just slightly out from under her smooth skin as she arched her back repeatedly.
“TELL ME YOU LOVE ME!” she ordered randomly.
“Ilena,” he called for his wife “I love Ilena!”
“YES!” the demoness screamed again “SAY IT AGAIN!”
“I love my wife! I love Ilena!”
“AND SHE LOVES YOU! SHE LOVES YOU SO MUCH! I LOVE THE TASTE OF IT! SO THICK!” at that she turned completely incoherent, screaming randomly and failing utterly to compose words. She didn't even slow down when her inner walls tightened and forced an orgasm out of Vern whose cock immediately started filling her with semen.
They rode off their orgasms and Xila's pleasure-addled mind eventually returned to her senses. She rested Ilena's body on Vern's chest, her muscles still twitching from the aftereffects.

“Servants,” she addressed “you both pleased your mistress well. The love you share makes the lust far more delicious than I thought possible.”
“Does that mean you will stop possessing Ilena now?”
“So, concerned, aren't you?” she noted with an amused snicker “As is to be expected. But yes, I am done riding her flesh for now.” With that, the glow in her eyes subsided and they went back to their normal blue color, while the candles went back to a dim burning yellow. The room looked normal again.

“Ilena? Darling? Are you alright? Do you remember what happened?”
She responded by sparing a look to the cradle and, assured that their child is sleeping safely, hugging her naked body to his “Yes, I'm alright. And I was there through it all.”
“You sure? I'm pretty worn out and she drove you even harder than me.”
“I told you I'm alright. Just tired.”
At that, Vern could relax. He hugged her back and stroked her hair. So fluffy. “Ilena, I'm sorry you had to go through that.”
“You have nothing to apologize for. I'm the one who got our souls sold and I would do it again. And the things she did while possessing me were... nothing I can't deal with.” 
Xila did actually go overboard with the cum drinking and Ilena could feel it sloshing in her stomach when she rode her husband. The feeling of that big dick actually going past her mouth and into her throat was also strange and uncomfortable, but Ilena decided to keep those details to herself. “She was feeding on our lust, I think. She didn't want to force things too far beyond what I found pleasurable.”
“Well that's a relief.”

Ilena snuggled up further and sighed in contentment before she felt something hard poking at her thigh. She rubbed her thigh against her husband's fully erect cock. “Oh? You must be feeling more than just relieved,” she spoke with a sly smile and rubbed harder “don't tell me you're still horny after all that.”
“Ah, Ilena, you beautiful temptress, you know I am. I think it's the aftereffects of the demon's spell. Your tits aren't helping either.” Said breasts were poking against his own chest and the nipples slowly dripped moisture onto his skin.
“You know I'm always happy to serve you. I'm a bit too tired to service you, but feel free to do as you like with me.”

Vern did just that. He gently rolled her over onto her back and gave her a kiss to the lips before moving his attention to her breasts. He kneaded and massaged carefully but firmly and Ilena immediately let out a happy sigh. “Whatever Xila did to me made them harder. You like them better now?”
“Actually, yes. They haven't felt this firm since we were fifteen. But they weren't half as big back then.”
His palms moved to the base and squeezed upwards, as if milking them and, sure enough, a few drops of liquid leaked out of each nipple. He leaned down and cleaned them both with his tongue before settling on her left breast and sucking. She moaned softly and her fingers ran lovingly through his hair. He then alternated between her breasts for a time, sucking on one and squeezing the other. A few times, he went down to her ribs and belly, lavishing them with attention before going back to her breasts.
Even as he felt the need to satisfy his rock hard penis, he kept giving attention to his wife. Vern knew it wouldn't take him long to cum once he was inside of her. If he was to give her an orgasm, he needed a head start.

He moved a hand down to her pussy and parted the lips. Some of the semen he deposited inside earlier leaked out, but he ignored it and fingered her, expertly using all the sensitive spots he found inside over the years. His mouth didn't let up on her breasts either either and her sounds of pleasure picked up the pace quickly.
He felt and observed her carefully and once he judged her ready he pulled out his fingers and brought them to her mouth. She obediently cleaned them and proceeded to suck on them gently while he positioned himself between her legs and slid his cock back inside her, burying it all the way to the base.
She reacted immediately, her legs wrapping around him and her throat giving out a deep moan which repeated itself as he thrust into her. When he lowered his torso to lay on her and kiss her, she put her arms around him too. Her grip was feeble, indicative of her tired state, but the feeling of her body surrounding his was no less pleasant for it. He let the weight of his body push down onto hers and her breasts pushed back firmly against his chest. 

They started their lovemaking slowly, with deep thrusts that thoroughly rubbed her insides. Even without Xila possessing her, Ilena's inner walls were tight around Vern's shaft, squeezing him far more firmly than a mother of two children ever should.
He kissed her forehead and traced more kisses along her jaw and neck while gradually speeding up the thrusts.
“Ilena,” he spoke into her ear “Ilena, you are beautiful.”
She tried to respond, but it came up as a jumbled mess of moans and half-words. Her mind was beyond words. 
Taking her highly aroused state as a sure sign that she was close to her climax, he picked up the pace. He was far too close to the edge himself, but he was also resolved to hold back until she was ready.
Fortunately, he had long found the key to making his wife finish, a sensitive spot just under her ribs. The angle had to be just right, the pressure feather light and his mind was plenty addled by pleasure, but he had years of practice. He massaged her special spot gently, fucked her pussy vigorously and she responded even harder than usual, Xila's lingering magic giving her a burst of stamina and driving her to heights of passion.
Her moan was so hard it turned into an aggressive growl while her body gyrated and rubbed against his. Assured that his husbandly duty was done, he let himself orgasm as well. They both lost control and enjoyed eachother's bodies wildly until they were satisfied.

When the haze lifted from their minds, they found themselves exhausted, the high of Xila's magic wearing off rapidly.
They rested, Vern on top of Ilena. He still had the strength to stroke her hair, enjoying its softness, and not much else. “Ilena, I love you.”
“I love you too darling. Now sleep. You are as tired as I am.”
With her warmth and soft words, he couldn't resist even if he wanted to and she blissfully followed him into the dream realm.