Before you stands a full-length mirror wrote from what appears to be solid silver. The frame is richly engraved and the heavy patina serves to highlight the elegant craftsmanship. The reflective surface is flawlessly smooth and devoid of any imperfection. Your image is reflected back to you with such clarity that it seems almost real, definitely more so than the bronze and copper mirrors you are used to. Just, when you look into the eyes of your reflection, you feel as if someone, or something, else is staring back at you.
The Story
In broad strokes, Kagami's backstory is centered around a self-centered and narcissistic young woman who, in her vanity, trying to seek eternal beauty, and in the pursuit of such found herself cursed to be an eternally beautiful mirror, reflecting the image of others while unable to recall her own form or name (Kagami being an assumed name she picked up along the way). Kagami has the power to alter those whom she reflects upon her surface, though this can normally only be done through great effort on her part, and while once upon a time, she did this to others out of spite, she has since mellowed out quite a bit. Once it was found out that one needed to be reflected upon her to be transformed, a simple cloth was all it took to render her harmless. The intervening centuries taught her the value of companionship, so when she is uncovered by the Champion, she is disinclined to do something at would get the cloth put back over her.The Mechanics
The primary benefit to the PC for acquiring Kagami is that she can transform the Champion in certain ways, primarily by memorizing the Champion's form and then transforming them back into that form at a later date. While doing this, she can either trade keep the saved form or trade it out for the one the Champion currently has.An example of this would be to have a Lupine form for playing with Kiyoko and a Dragonoid form for Daliza and/or Aileh.
As the Champion is more malleable than most others, Kagami finds it easy to change the shape of the Champion, but there are limits to what she can do. Certain permanent transformations cannot be overwritten, such as the form given when pledged to a God, nor can she undo demonization, as her powers affect the form only, and not the soul. She will also not do anything to harm unborn children, so she won't delete a womb while the PC is pregnant.
While Kagami is trapped within the mirror and can't come out, she can temporarily pull people into the mirror realm she resides in (technically, it is just her avatar, since the mirror, itself, is her physical body).
Possible Companion Interacts
Agnimitra - [WIP]Arona - Kagami could either show Arona a subby side of herself for Arona and the Champion to dominate, or both can gang up on the Champion.
Atugia - [WIP]
Azyrran - If Kagami is shown the different personalities of Azyrran (Bimbo and Dom-Dragon), she can assume one of those personas, while Azyrran is in her normal state of mind or in one of the others.
Brienne - Twin Brienne. I'm sure she'd absolutely love it. If Kagami met Brint before he transforms, Kagami can assume his form and she and Brienne can RP out Brint being forced to submit to the Champion (again, something she'd probably love). While Kagami would technically have the power to change Brienne's body back into Brint's, she cannot do change the personality within, and as Brienne would be unwilling to return to being Brint, that is not something Kagami would force on her, especially given the effort involved.
Brint - DP and Spit Roasting scenes with the Champion. As the transformation into Brienne is a one-way street, there is no interaction with Brint and Kagami-as-Brienne.
Cait - Obligatory Twins, maybe with a player-two style palette swap with the hair dye (baby blue instead of pink). Kagami would also be able to take on one of Cait's forms that have been shown to her (Thicc Cait vs Leo Cait, anyone?). It might be possible to de-Leo Cait using Kagami's powers, though it would take effort to do so (final say would be Cait's writer).
Etheryn - Kagami can assume one of Etheryn's transformations and also act out one of Ryn's personalities (libido/confidence combo). You could show a confident Ryn who is busty and thicc just how far she's come from the normal and shy Ryn was was before.
Kiyoko - I don't know if Kiyoko would be all to thrilled to play with Kagami, and due to the nature of Kiyoko's transformations and where they take place, I don't see a plausible way for Kagami to see any of Kiyoko's other forms.
Quintillus - [WIP]
Viviane - Kagami could potentially play with Viv's form, like she does with the Champion, but I'm sure Viv would have countermeasures to prevent such tampering. Don't know to what extent Viv would let Kagami play with her form, but they'd probably have fun together, none-the-less. Kagami wouldn't be able to revert Viv's demonization, even if she had met Viv beforehand, as stated earlier.
There is potential for a quest where the Champion transforms themselves into a very specific way, following Kagami's instructions. The goal of this is to create a form for herself that she can call her own.
There is also the potential to train her to get some more 'sort' to hold more forms for the Champion to transform into.
Asset-wise, Kagami would only need artwork for the mirror, and a clothed/nude for her own form if/when her Quest was implemented.
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Let me know what you guys think.