**Setting notes: I have borrowed the Serenity Amaris version of Usagi from one of my favorite authors, Sesshy's Mistress (who I have been following for... what, over a decade now?). If you aren't familiar... go read her stuff (u/1378005/Sesshy-s-Mistress). Seriously. If you are interested in reading this, there is no reason you won't want to read her SM/Kuroshitsuji crossovers. But, basically, Usagi is now Cosmos, has made a new life for herself as Elizabeth's cousin, and was rather dismayed to find her beloved cousin's fiancée has a demon butler. Sebastian, on the other hand, has no idea what she is, and is completely fascinated.

Moving on... I always have multiple fanfics going... in my head. Never actually get around to writing them down. Until I'm up all night having had too much energy drink, apparently. This is short, I suppose it might be more of a drabble. The title was not considered all that much, it just seemed to fit. This was written in one sitting at about 6 am after no sleep, then fussed over for about a month before finally being posted as it was. Let me know if you find any mistakes (Oh, and, uh…. Stay away from my old stuff. I was 12. It is horrible. I was asked not to take it down by some old fans, but… really. Bad, bad stuff. The one a few years back is probably ok.)

Serenity sighed as she rolled over yet again, seeking a comfortable position that would let her at last find slumber. At her cousin Elizabeth's request—pleading, really— she had reluctantly agreed to an overnight stay at Phantomhive manor. But the moon was full, and she was restless. She wanted to be outside. She wanted to run through the trees and race with the wind under the moonlight. Her eyes tracked a lone firefly outside her window, one of the last survivors of the season. If she went out, there was a very good chance a certain demon butler would find her... but, tonight, that was not enough of a deterrent. She finally sighed and got out of bed. Opening the wardrobe, she frowned when she was greeted by skirts. Not great for running with the wind, but women didn't wear pants in this century. Forgoing any finery, she put on a simple white skirt usually used as a petticoat under her dresses. Anxious to get outside, she hiked the front of it up to her mid-thigh and tied it in place.

The night was comfortably warm, the breeze invigorating. A smile broke out as she stepped barefoot onto the bare earth, and with a brief look around to make sure no one was watching, she took off towards the forest. The wind made her heart soar, and she felt almost as though she were becoming the moonlight itself, traveling at incredible speeds through the world without weight or care. She felt the heartbeat of Jupiter in the trees, the caress of Uranus in her hair. She adored nights like these, when the fresh air and moonlight seemed almost literally intoxicating.

She slowed as she approached a clearing. The moonlight was bright here, filling the space in a way she could physically feel. She walked through the tall grass, smelling its sweet scent. A stream ran through the clearing, glistening alluringly, beckoning her over.

As she knelt to dip her hand in the cool waters of the stream, she felt a familiar presence watching her.

"Will you follow me everywhere?" She asked, but without any fire. With the light of the full moon shining down on her, she felt at once both relaxed and wholly alive— and, for some reason, not as annoyed at his presence as she usually would be. She was too caught up in the night around her.

A shadow detached from the tree line and made its way to her side. She stood smoothly and turned to face the demon butler. An almost sly smile curled his lips as he took in the sight of her — face flushed; skirt hiked up to give her legs freedom to move (utterly unladylike; utterly desirable); a content look in her eyes that was almost erotic, holding both a spark of vigor and the look of one whose desires have been satiated.

(Later, reflecting on his unusual loss of self-control, he would realize it was that look in her eyes that had undone him.)

"I merely wanted to make sure our esteemed guest was alright", he assured her in his usual subservient manner. As she turned away slightly to follow the path of a firefly, he continued: "Naturally, I must attend to my master whensoever he has need or desire of me."

Before her gaze could return to him, he was suddenly behind her, his breath hot against her ear as he whispered, "But it is the dead of night, and my master sleeps."

Perhaps goosebumps would have erupted over her flesh then, except that she was too startled from finding herself flat on her back, hands pinned by the demon as he loomed above her. His eyes were glowing red and the mischievous spark generally present whenever he cornered her had become something almost fierce. Entirely against her will, her heart started pounding.

"A little bunny could run into trouble, out alone in the woods," he purred, referencing the nickname given to her by her young cousin. She attempted to glare at him, but was distracted when the hand not pinning her wrists above her head came to rest on her waist. She acutely felt the warmth of his body on top of hers.

"This bunny happens to have claws," she managed through gritted teeth.

"Oh, I'm well aware," he chuckled. It was one of the things he loved about her, in fact. Tonight, however, he had no intentions of letting that distract him, as enjoyable as those fights were. "But a bunny is still prey to a ravenous wolf who wants to... devour her."

She flushed redder at his words, the look in his eyes letting her know exactly how he wanted to devour her. She fumbled for words as the hand on her waist trailed down to her thigh. Feeling his hand against her naked skin reminded her of her previously forgotten state of dress. She once again cursed the era for its lack of female pants. She also noted that his hand was free of his usual gloves, and that his skin touching hers left a trail of fire as his fingers slowly drifted back up, nudging her skirt even higher. Her traitorous body was reacting against her will, and if she had been in her normal state of mind she would have wondered why she wasn't putting up more of a fight.

"What wolf?" She countered, her voice somewhat hoarse. "You are only a crow." Her response seemed to her like it was delayed, like a comeback thought up too late after the initial insult, but in reality it had been hardly two seconds. Time seemed slower, somehow, as her brain lingered on his proximity to her, and how he lay— how did that happen?!— with his lower body between her legs.

His eyes narrowed at her words. "I'm versatile," he said shortly, before suddenly thrusting his hips against her core. She couldn't help the startled gasp that escaped her. This was far from his usual level of teasing! She didn't want to admit it, but her body ached at the contact. It had been a long time since she had felt the attentions of a man, and Sebastian was fuel for any woman's desires. And, of course, he teased her every chance he got, building up the simmering tension always between them.

'It's the moonlight', she thought. 'I would never tolerate this otherwise'. She mentally slapped herself when a part of her was suddenly grateful for the light of her former home. 'You are not enjoying this! Demon, remember?! He's a demon!'

It didn't help that he was no longer hiding his desire for her behind his butler facade; in fact, the evidence of it was pressed intimately against her. He leaned down to trail his lips down her neck, his free hand gripping her hip beneath her skirts, holding her still as he briefly ground into her once again. He reveled in the feel of her body trembling beneath him. Unwilling to wait any longer, he claimed her lips with his own, nearly groaning at the taste he had longed for since his last stolen kiss. The movement of his hips caused her lips to part in a half-stifled moan, and he took full advantage, caressing her tongue with his own. As always, the taste was brief; he knew to withdraw before she had the chance to bite.

Finally regaining some of her senses, Serenity jerked her head away, ignoring the frustrating reluctance to break the searing kiss. For a moment she could do nothing but catch her breath, and in that moment his lips were again brushing against her neck, sparking a sensation which seemed to shoot straight between her legs. She fought back a whimper of desire and tried to buck him off. This turned out not to be the most well-thought out plan, given that this only thrust her pelvis more firmly against his, and she was startled when the demon stiffened and groaned at the added friction. The sound of his own desire sent another wave of fire sweeping through her, and she fought even harder to muster the willpower to put an end to the encounter.

Sebastian suddenly went utterly still. Grateful for a chance to calm her beating heart and catch her breath, Serenity looked up at him as he lifted his top half off of her. His eyes were hard with suppressed passion, and although he kept his expression neutral, he was clearly frustrated.

"My contract with my master, while at times wearisome, has never been a cause for regret," he said stiffly. "Until now."

Relief swept through Serenity as she realized that he was being summoned. The burden was off her to put an end to what was happening, her internal struggle ended. Of course, the fact that she hadn't blasted him off her before now was one he could (and most certainly would) use against her in the future...

Her thoughts were interrupted when Sebastian yanked her head back and assaulted her lips once more. "You can be certain that this isn't finished", he promised with a growl, before vanishing into the night. Serenity was left with a pounding heart, a whirling mind, and an ache between her legs that screamed at her its frustration at Ciel's interruption. She groaned and closed her eyes, telling herself it was good that things hadn't gone further. Really. It was good.