/////Ball-jointed Doll character. Her body was crafted and painted by the artist leading the ivories. None of the colors matter. Copélia!
She stands 3 feet tall in a pastel lolita-style dress with a skirt that flares out above her knees. Her legs have thin stockings too sheer to hide the joints, and her back sports a very large bow, wider than she is, almost like butterfly wings. Upon her head are short, segmented horns that sweep back before curving up, and her platinum blonde hair descends from her like strands of white-gold.
Her skin is smooth, matte porcelain, painted by an expert.

She yearns to be admired and obsessed over, and she loves to dance. In some performances, and in combat, she uses magic to undo the bow on her back, gliding it through her hands as a dancing ribbon, about 10 feet long and 2 inches wide, wider than her hand.
///Rough notes of possible content if she is not just a miniboss in a dungeon
Her need to feel the wanting gaze of others means anything that has her being watched appeals to her. She would love to have the player request she perform, even showing her body, with plenty of prose on the detailing and joints as she strips.
Would Tel'adre be possible to fool? She's 100% corrupt, but they're a little useless and an imp infiltrated that place (Scylla content), so you passing the checkpoint and them not checking what looks like—and is—a doll makes some sense. She would like to perform for a crowd. But fuck Tel'adre, I wouldn't write that. If I did something like that, it'd be the Bazaar, which already has revelry of sorts. That said, she's child-like in shape. Magnificent artistry, and someone thinking with more than their cock would find her performance enthralling, but this is CoC. Still, I want to take her on a date to the Bazaar for:
//Extra Outfits
/Telly's simpler and modest style, an A-line sundress
A bright yellow sundress adorned with flowers on the hem.
/Greta's more sultry and skimpy style, a harem dancer. Teal?
Flowy sheer pants that billow softly around the legs, cinching snugly at the ankles, and a thin, silky crop-top that ends just below the sternum.
/Taking her to Marielle for a far far more elegant and elaborate piece of lolita fashion would make sense too. Given Wombat's inclinations, Shinku's outfit? I haven't read Rozen Maiden yet, don't know if there's something more suited to a dancer in there.
A thin capelet and dancing gown?
///Sex scenes
Strip tease. Experimented a little with writing that for Shouldra, I could experiment with more.
Thigh job, emphasizing her smooth sculpting of the vulva that looks alluringly real yet cannot yield to penetration.
Foot job. Feet are feet? Not soft, but they're certainly be leagues prettier than real feet.
Scissoring. Mind you, she can't feel with her body, she only feeds of your desire for her, so this might be thematically ill-fit
Mouth stuff? I imagine her face is something in between rigid fired clay and soft skin, where it's firm but moves, but her mouth cannot open very far.
Hair job. Finally an excuse to write another hair job after 5 years. The moment nobody has been waiting for.
///Backstory
As an Alice, she has lost everything that matters to her. All her sexual assets were gone, her body weak, her capacity to enhance herself stricken as her flesh no longer responds to black magic or alchemy. And of course, all demons hate Alices, leading them to torment or ostracize any that come. She had no friends, no allies, and no way she could imagine she'd ever sate her unending lust again.
But one demon was willing to accept her in. The obsessive artist who created the ivory succubi, an artist who insatiably molds his underlings into his own living masterpieces.
What choice does she have? To finally be accepted, to finally be desirable, to finally have it all again...
And so, to work around her uncooperative flesh, every bit of biological extraneity was carved away, with only the head and heart maintained, and with great effort to preserve. A new body was made, every component sculpted by his masterful hands, and what little of her flesh needed being bonded with clay for a uniform look.
This new body cannot feel or sense. Her sculpted and beautiful vulva can not flex or spread, there is no hole to penetrate. She has lost any ability to indulge in sex as she once did.
Yet when she sees the eyes of those that marvel at her craftsmanship and grace, she receives the sexual energy she needs. She lives in a delusion, she wouldn't be able to handle it if she had to confront the reality of being forever barred from physical intimacy. Instead, her mind is fixated entirely on seeing the hungry eyes of people that watch her dance. She won't think of herself as the one unable to experience sex, but they, who watch, that are missing out on it. It is them that don't get to experience her body no matter how tantalizing she presents it.
She's a playful, cheerful character, and only ever a tease.
//////////ENCOUNTER (maybe). A mirror duet (pas de deux) ballet, include elements of balletic pantomime. Both Copélia and her ballet partner share status effects, perhaps they cannot be defeated unless they are both under 10% HP. Maybe take inspiration from a Faust ballet, on-point for what she is.
////In the encounter, avoid anything that makes it evident Copélia is a living being, try to indirectly imply she's just a tool, a conduit for the other demon's magic to put on the performance. When Copélia is too worn out to fight, she can't cast white magic, and white magic is the only thing that lets her body move since it isn't biological, so she goes completely stiff. The outcome of the battle focuses on the other demon, with typical options you expect, and Copélia is unceremoniously added to your inventory as Ball-Jointed Doll. You can do various things to her while she's an item, but after a brief time, she will recover, and if she's in Storage, she will make a huge fuss about it. If you did perverse things with her while she was inanimate, she will feel more haughty. If you just tossed her into the trunk without a thought, she will be very offended. She'd also be happy if you posed her and left her on display.