As soon as he leaves, she climbs back into her cage. The door he came in through seals shut and merges with the wall, and she can feel the stairs withering away until the next time they're needed, and she closes her cage door and closes her eyes and reaches out to her power.
The counterfeit invitation is a little too small for her to directly feel it lying on the floor, but she can tell that her power is looking at it and shifting category boundaries in response to the new information. After a few seconds, when her power finishes analyzing it, it melts away silently into the floor.
She knows what's coming next, but even so, when she feels the cold metal of the cage start to shift and flow and twist around her, she flinches and struggles. It doesn't make a difference; it only hurts her more. Her power knows what to do. She's been bad, she made a mistake that almost cost her master everything, and now she needs to be punished.
The metal wraps around her wrists and ankles, pulling her hands behind her back and forcing her legs wide apart. She trembles with fear, crying harder. It's always worst when it's something sexual, and after what Master just did to her it'll be even worse than that; but that's good, that's correct, she should be tortured after what she did, she should be terrified and miserable, she should be shaking and crying and struggling futilely against her self-imposed restraints.
Something touches her, somewhere between her legs; she can't tell precisely what or where because all detail is obliterated by the stabbing jolt of pure agony that follows. She whimpers loudly. It happens again, worse; she pulls desperately at her chains for a moment, then swallows a sob and stops trying. Struggling is useless, and anyway, she deserves this. She should accept it. She should be glad she's being punished this way. She should be glad that all touch is pain, and that pleasure is the worst pain of all.
The contact happens again, and this time it's more than a brief touch; she feels something enter her, slowly, sliding deep into her bleeding cunt. It feels as big as Master's cock was when he was finished hurting her with it. Bigger, maybe. And it moves so slowly, giving her time to feel how the pain rises as it fills her, how it drags at the places where Master tore her open. And then it pulls back, just as slowly, and pauses when it's just barely touching her, and starts again.
It hurts, enough to be torture even if the pain was the only thing to it, but it's not. She knows exactly how this is going to end, and there's nothing she can do to stop it.
She hangs limply in the air and sobs with pain and fear as her own magic rapes her. And the pain builds, and builds, and builds, in a too-familiar pattern; the thing that's fucking her moves faster, thrusts harder, and the pleasure her body is feeling turns to pain before it ever reaches her but her body still feels it as pleasure—
Near the end, she loses control of herself and starts struggling again. It doesn't matter. She can't fight this, and anyway she deserves it.
The relentless rape drives her body to orgasm, and when it hits, she screams. Wave after wave of white-hot shuddering agony tears through her, and it's all she can do to stay conscious, until finally she fails at that too.