[X] Remain calm, be patient. You can outlast Riona's stubbornness.
-[X] Alternate pressing main points with other topics.
[X] Offer and get refreshments (without leaving the bubble).
[X] Explain and reaffirm your goals:
-[X] To help Magical Girls, to break the system.
-[X] Your intentions when Wishing.
-[X] People can do horrible things, when forced...
--[X] Your goal isn't to take away Riona's power, but to give her a chance to do better.
[X] Points to press:
-[X] Riona won't achieve her goal by refusing help.
--[X] If this really matters to her, she'll need to make compromises.
-[X] Her shades are actual Souls. What she's doing is inhumane.
--[X] You won't begrudge her keeping voluntarily given Souls.
--[X] You'd gladly help if she wanted to revive them.
--[X] If she wants them for protection, there's alternatives.
-[X] We.
--[X] Can.
--[X] Help.
[X] Other topics:
-[X] What does your Soul look like?
-[X] How do her powers work?
-[X] Wish rejection: describe Oriko's symptoms.
-[X] De-Witching.
--[X] Let Riona examine Aurora.
--[X] Explain your experiments so far.
I think that it's not time yet to "settle in for the long term", and it's probably not as risk-free as it sounds. If nothing else, Riona's bluntness makes it nearly impossible for us to filibuster - she burns through topics too fast and she's more than willing to cut off discussion and say "we've already covered that, next topic". All of these topics are things we've more or less already covered, especially since at this point she's probably going to refuse share more information about her power.
[x] She won't give it up now, fine. But would she keep those souls trapped, if it truly became no longer necessary?
[x] You're not going to invade her privacy and you don't want to, but you can't think of many ways a girl gets a power like Rionna's.
[x] You want Rionna to stop murdering people, and if any of her shades are suffering you want that stopped.
[x] But. But. If any of her shades are someone she wanted to save... you won't ask questions, and you'll provide all the assistance she could want with that.
[x] Does that deal sound like what she needs?
Rewriting for clarity.
[x] Plan:
-[x] She'd be unwilling to give up her sister's shade and you think she might be equally unwilling to reveal that she has it.
-[x] You'll make a stab in the dark about her power's origin and use it as grounds for giving her a way out.
-[x] Make an offer that would let her keep her sister's shade without talking about it.
-[x] Note that, if she is holding her sister's shade, she's likely denying the ethical implications of her actions out of self-defense.
[x] She won't release her wraiths now, fine. And you won't deny her her home or safety. But would she really keep those souls trapped if it became unnecessary?
[x] You want Rionna to stop murdering people, and if any of her shades are suffering you want that stopped.
[x] But.
But. You can't think of many ways a girl gets a power like Rionna's.
[x] If there are any shades that she
needs to keep, and she doesn't want to explain who they are or why she needs them, you won't ask questions. You'll just assume she's trying to save or restore someone and help however you can. It can't be harder than dewitching, right?
[x] Does that sound like what she needs?
edit: ...Blast, this is what I get when I don't refresh after finishing up writing a new vote.
[x] She won't release the wraiths now, fine. You've no intention to ask her to lose her city. But would she still keep souls trapped in the future, if it truly became no longer necessary?
[x] You're not going to invade her privacy and you don't want to, but you can't think of many ways a girl gets a power like Rionna's.
[x] You want Rionna to stop murdering people, and if any of her shades are suffering you want that stopped.
[x] And if any of her shades are someone she wants to save, or restore... you won't ask questions, and you'll provide all the assistance she could want with that.
[x] Does that deal sound like what she needs?
edit edit: Incorporated these changes.