I do not own anything written by Rumiko Takahashi.

This has the first high-citrus content of the story. I hope I've toned it down enough for an 'M' rating, the description is rather general—certainly, this isn't any worse than what you can find in modern romances that minors can buy off the rack. The full, unedited version is available on AO3.

Origin

The Succubus is a nature spirit, though considered to be demonic by Christians during the Medieval Era. Originally restricted to Europe, they have followed Europeans throughout the world and now can be found wherever Europeans have settled in large numbers, though Succubae have had limited success in spreading beyond those settlements.

Description

The Succubus takes the shape of a naked and beautiful, or at least cute, human female in all of the shades of skin and hair color found throughout Europe. In its natural form it is invisible to almost all non-Awakened humans and incorporeal to all nonliving substances. As it matures, it gains the ability to temporarily become visible to Sleepers in whatever human form it chooses of either sex, and is able to appear dressed however it wills when it does.

Habits

Succubae are nocturnal predators. They feed off the energy produced by lust, merging with their victims and inducing erotic dreams to produce the required stimulation. The victim usually dismisses the entire incident as just another erotic dream, leaving the nature spirit free to repeatedly feed on the same people without arousing suspicion. Succubae are universally bisexual, feeding on men and women with equal enthusiasm and taking whatever dream form needed to sexually arouse their victims. Usually, they allow the dreamer to shape the dream and merely fit themselves into whatever partner and activity the dreamer comes up with, though Succubae can take more active control if they choose.

Succubae are able to reproduce by collecting sperm from a human male through physical sex (though usually using its ability to control dreams to keep the victim asleep through the entire encounter), and then forming a penis and impregnating a human female (again, keeping the victim asleep). Succubae have a mating instinct that drives them to do this on a yearly basis, and the female hosts always become pregnant, whatever point they might be at in their monthly cycle. Most of these pregnancies will seem to miscarry at about the third month of pregnancy, but will actually produce an immature Succubus that will be left to survive (or not) on its own — most do not survive to maturity, falling victim to supernatural predators. Those that do survive reach full maturity in five years, after which point they are virtually immortal, unaging and with few natural predators. The very few male children produced by such unions are fully human, though universally born Awakened and often of a high level of power. Such births have produced many of the most famous mages in history — Merlin is the best known, but far from the only example.

Succubae are very hard to permanently destroy. Their physical bodies may be destroyed normally, but upon 'death' they merely dissipate only to reform (starved for 'food') when night falls. They may be driven off or captured by the appropriate magical rites, but it requires damage from a supernatural creature or magically-imbued weapon to permanently kill one...

— An Introduction to the Nature Spirits of Europe, by Professor Albus Dumbledore.

Hikaru Gosunkugi lay in his bed and glared through the darkness toward the unseen ceiling, grinding his teeth. The rumor mill at school had been working overtime like never before, the entire student body abuzz over the sudden change in Nabiki's demeanor. The general consensus had been that a guy had somehow gotten through Nabiki's icy shell and found something resembling a real woman, though Akane had vociferously denied the possibility. A few students had agreed with her reasoning, but most simply shrugged it off as Akane having her own not unreasonable problems and most of the speculation had been over just who her new beau was. Suggestions had ranged from one of the students (with a large betting pool forming over which one it might be), one of the teachers (another, smaller betting pool), or perhaps a family friend, skilled in the martial arts and able to provide enough protection that she could relax (a very small betting pool, since this one was a yes-or-no question, nobody knowing any such Tendo family friends). No one had asked Gosunkugi for his own opinion, of course — if there was anyone in the school as socially isolated as Nabiki it was him — but he knew and this time knowing something that nobody else did wasn't the joy it usually was, because Nabiki and summoned and bound her own personal nature spirit fucktoy.

He had long known that Nabiki was a practitioner of the Mystic Arts, of course. Her Awakening several years ago had been impossible to miss for anyone in Japan's mystic community that saw her, and Gosunkugi had been amazed and a bit jealous at the level of power she'd manifested. Still, he'd been able to console himself with the fact that, while powerful, she was completely untrained while he had the knowledge and traditions of his family's generations of immersion in the Arts to draw on — strength is fine, but useless without the knowledge of how to use it, and his ancestors had been shadow advisers and protectors of emperors and shoguns, high in Japan's shadow aristocracy. His jealousy had been born when he'd come across her purchasing supplies in one of the few stores that catered to the real Initiates and realized that she was actually learning how to practice the Art instead of being satisfied with whatever innate talents she might have acquired since her Awakening. Still, he'd told himself that, in spite of her power, she'd never have the resources he had to draw on and so could never be his equal. That had changed the other day, when he'd passed her in the school hall accompanied by a busty, cute, and obviously natural red-haired humanlike nature spirit. It hadn't been hard to figure out just why Nabiki had bound that spirit to her, and the daze she'd been in when he'd seen her at lunch today had just confirmed his suspicions. Now, with the knowledge that she'd succeeded in a summoning that he'd failed over and over, his envy flared to toxic heights to mix with old jealousy and the white-hot anger that resulted ate at him like cancer.

Finally he gave up on sleep and, quickly getting dressed and slipping unnoticed out of the house, he headed for the Furinkan school and an isolated and overlooked shed (thanks to his ritual of avoidance) on the school grounds. He would teach that upstart bitch of a nobody a lesson she'd never forget!

/\

Gosunkugi gazed in satisfaction through the slight haze of incense smoke at the imp crouched within his summoning circle. Details were difficult to make out in the flickering candle light, but didn't really matter — one imp was as good as another, weak and not particularly intelligent, but useful as scouts and spies if their instructions were clear. He cleared his throat, and in what he fondly considered a commanding tone he said, "You understand you instructions? You are to spy on Nabiki and her new red-haired spirit slave, and report back to me, at the school, not my home, when you know its true name."

"Yes, master," the imp replied, cringing slightly. You've only repeated it three times, it mentally added scornfully to itself.

"Very well. Go, and do not return until you have fulfilled your orders," Gosunkugi intoned, then scratched a break in the summoning circle and cracked open the shed door. In a flash, the imp was through the circle's gap, out the door, and off into the moonless night.

/oOo\

As the imp known as Gorash ran through the quiet night toward the Tendo dojo it snarled in anger and injured pride as it thought about the "master" that had given it its marching orders. What a complete idiot! He didn't even try to dominate or bargain, he just gave me my 'orders' and sent me on my way. He didn't even try to learn my true name! Too bad I couldn't tell him what to do with his 'orders', but Mara's general directive was clear — until she says otherwise, that moron is to think he's the greatest summoner of the age.

Noticing a stray cat in an alley as it passed, Gorash backed up to walk unseen past the wino sipping from his bottle and up to the cat. The cat saw the imp, of course, and hissed at the intruder in its territory. Gorash's head instantly ballooned to four times normal size, bared a set of fangs to do a tiger proud, and roared. The cat instantly backed up in a crouch, then turned and fled yowling into the night. Gorash's head returned to its normal size and it walked back past the puzzled wino staring after the fled alley cat, feeling much better. Nothing lasts forever, Gorash consoled itself as it again started running toward the dojo. Eventually the idiot's usefulness will be over, and then that overbearing bastard is ours! A vicious grin crossed its face as for a moment as it contemplated the fun the demons would have 'playing' with Gosunkugi when the time came, then disappeared as the entrance to the dojo came into sight. Ah well, to work, it thought and started to circle the premises.

/\

A short time later, Gorash was back in front of the dojo entrance, disappointed but not surprised. A ward covering the entire property, without a single gap and too strong to break through, much less without being noticed — and after only a year's practice, impressive. I can see why Mara is so eager to get this Nabiki working for us, and to become one of Mara's lieutenants when her time comes. Now, that's a mistress I'd be proud to serve under. Gorash walked to the home across the street and slipped behind the rose bush beside the front entrance. Nothing for it but to wait until she goes to school and try and follow her without being noticed, and hope she lets something slip, then see if Mara wants the moron to have that particular bit of information. Gorash sighed as it settled down. Yeah, right, 'just'. Nabiki isn't an idiot. This is going to be a long assignment.

/oOo\

Meanwhile, in Nabiki's bed (sort of):

The fog cleared and Ranma looked around at another opulent bedroom, curtains hung around the bed — carpets really — tied to the posts of the bed's canopy, more carpets hung on the walls embroidered with scenes from European history and mythology, everything indicative of wealth beyond his father's wildest dreams. Glancing down, he found his male body dressed in a worn and dirty gi instead of the red shirt and black pants he had picked up in China.

"Well, well, I'm certainly happy to you again," said a familiar voice behind him, sounding pleased. Ranma turned to find Nabiki lounging in a chair against the wall by the entrance, dressed in a two-piece lingerie. She rose and sauntered toward him, a hungry smile on her face. One of her arms went around his back, the other pulled his head forward and slightly down into a searing kiss. Ranma's hands dropped to massage her butt-cheeks, left bare by her thong, and pulled her groin against the growing tent in his pants as an unfamiliar feeling of rightness and eagerness swept through him. Nabiki chuckled throatily. "Well, it seems you're happy to see me, too." She pushed back and started undoing the ties to Ranma's gi top as she commented, "It's unusual for me to get the same man from one of these dreams to another, and you aren't my normal handsome prince. Just what is your name?"

In a voice made husky by desire, he responded, "Ranma Saotome."

Nabiki's fingers froze on the ties even as his gi top fell open. Then she abruptly pushed out from his embrace and took a couple of shaky steps back. "It really is you, isn't it? You aren't just a figment of my imagination, y-y-you're the real thing!" she stammered.

Ranma nodded in response to Nabiki's stunned question. "Yes, I am," he managed to get out as he stepped toward her.

Nabiki thought back over the way the red-haired female nature spirit she'd befriended had covered herself when they'd first met — had blushed and stammered at the least hint of physical intimacy — and managed to ask through her rapidly growing lust, "Ranma, are you sure about this?"

Ranma paused for a moment at the question. Something wasn't right, something inside him was shouting that he wasn't like this, but a need was growing in him to fill an odd emptiness at his core that he vaguely remembered from the previous dream, making it hard to think and drowning out that shouting voice, burying it to a faint echo — his response was to pull Nabiki into another deep kiss, his hands running smoothly over her back and ass.

"I guess you are," she murmured against his lips as her hands followed suit, "let's see if you remember last night's lesson..." She ran her tongue from one corner of his mouth to the other, then used it to push his lips apart and began a duel with his tongue as her own need grew.

Ranma was enjoying the feel of their tongues intertwining, Nabiki's breath on his skin, the taste of her mouth, groins pressed together. But the need for something more was growing stronger, and Nabiki yelped as Ranma scooped her up in his arms and carried her to the bed, sat down on the edge of the bed with her seated across his lap, then eagerly resumed the tongue duel. As the kiss continued, Ranma's left hand drifted to her lingerie top's tie behind her at chest level and slowly pulled the bow apart, then did the same with the bow behind her neck while his right hand softly stroked her stomach and then up along the underside of her breasts. As Nabiki moaned at the little bursts of electricity the soft touch seemed to send ricocheting through her body, Ranma felt something trickle into the void at his core, slowly beginning to fill it.

Nabiki broke the kiss and sighed with pleasure as she slid the untied top down her arms and tossed it aside, neither of the two lovers noticing that it vanished before hitting the floor. Ranma's fingers moved from the undersides of her breasts up through the valley between them, then over one breast while his head dipped down to the other, suckling and nipping as the flow into his core strengthened.

Nabiki's moans deepened at the attention her orbs were receiving. She ran her hands along Ranma's back and stomach, working them under his undershirt and pushing it upward as her left hand moved up his stomach to rub his chest, returning the favor. She protested inarticulately when Ranma stopped playing with her breasts, then sighed in relief and renewed pleasure when he quickly slipped off his untied gi top and lifted his undershirt off over his head and tossed it aside (both garments following Nabiki's top into nonexistence), then renewed his assault on her chest with right hand and mouth while his left hand resumed stroking up and down her back.

Ranma was enjoying the flow of energy into his void, but it still wasn't coming fast enough! Thinking back to the previous night, he continued his mouth's licking, sucking, and nipping while one hand slipped down across her stomach to slip underneath underneath her now soaked thong. Nabiki gasped, jerking slightly at the touch and swinging her left leg out to give Ranma greater access as her left hand rose to take over playing with the breast Ranma had abandoned and her right hand began rubbing against the tent in his pants.

Ranma shivered as the rate of energy flowing into him jumped again, and Nabiki's moans grew louder as she began to jerk slightly in his arm, unconsciously trying to pump her hips. Suddenly, Nabiki stiffened and screamed, only the hold of Ranma's left arm keeping her in his lap, and Ranma shouted as the energy he had been savoring exploded into him. But it wasn't enough….

Nabiki went limp against Ranma's chest as aftershocks pulsed through her and her thoughts came back online. In the back of her mind something was nagging at her, not right…. Did I hear Ranma shout? But why would he shout when I orgasm ... ? She glanced up at Ranma's face. Are his eyes glowing? Then her thoughts derailed again as Ranma slid his right hand out of her now-soaked thong, under her legs, and picked her up and swung around to lay her down on the bed they had been sitting on. Nabiki gasped as he stepped back and untied his pants, quickly shoving them down along with his boxers and stepping out of them. Then Ranma stepped forward again and eagerly, almost roughly, gripped her thong and slid it down and off her legs and tossed it into disregarded oblivion.

Both of the two now completely nude, Ranma crawled onto the bed and between the legs that Nabiki eagerly spread open before him. She reached down and guided into her, chuckling throatily. " 'Wild Horse', indeed! Come on, show this mare how well you remember your lessons." Then she yelped as Ranma just growled in response and buried himself in one thrust. She resumed moaning and panting, words lost in the pleasure again washing through her body in waves as he started pounding into her.

Ranma was also finding himself riding waves of pleasure, as each wave of pleasure echoing through Nabiki sent a corresponding spurt of energy into his core's void, slowing filling it. Eager for more, he picked up the pace, to Nabiki's delight. She began reciprocating thrust for thrust, giving out little gasps and mews of pleasure each time their hips smacked together. Her eyes rolled back in her head, then her back arched and she screamed out Ranma's name as all higher thought vanished in a climax that dwarfed anything she'd experienced before. Her scream was again joined by a roar from Ranma as the explosion of energy exploded into him, overfilling his core's void and radiating out. He collapsed on top of Nabiki, then rolled to the side onto his back.

Nabiki was barely aware of this, as she lay shuddering. Slowly, her scattershot thoughts started to again come together; as something nagged at her — something wrong with what she was seeing, or rather how she was seeing. Was the room brighter ... ? Wearily, she rolled her head to the side, looking at her personal perpetual pleasure machine, then stared in shock. "Ranma, why are you glowing?"

Her question seemed to echo through Ranma's mind, as if from a distance. Slowly, his thoughts resurfaced from the depths that explosion of energy had driven them to. "Huh? Whazzat?" he muttered blearily, and turned his head to gaze at his lover's features, clearly visible in the light filling the room. Then the memory of what they'd just done, unclouded by need, exploded into his mind.