Warning: Potential mild violence in comments, if your character would like to fight Ganon in her dream. Also, the "descendant" described below looks just like OoT!Zelda, but if your character knew TP!Zelda, feel free to let them alter her image accordingly.
[She's suspended in a world of darkness, trapped behind the light pink glass of her prison. Somehow, she sees herself from the inside and the outside at once.
Inside. The tint of the glass gives everything a rosy glow, but it's false. The storm clouds outside are menacing, and they hide evil within their folds. An evil king. A demon. Ganon.
Outside. Suddenly the clouds part to reveal a shock of blond hair and a pale gown, one girl trapped in the midst of darkness and facing the beast alone. This is not her. She's still trapped in her crystal prison, but this girl...she knows her. Without knowing her, she knows. Her "descendant".
She pounds against the glass, crying out as Ganon advances upon the girl. There is nothing she can do but watch, as she feels the darkness holding her, choking her, trapping her so that the evil beast can reach her and cut her down. She cannot tell any longer whether she is herself or her descendant. Perhaps she is both. For this moment, perhaps they are the same.
'Someday, when this seal is broken...that is when I will exterminate your descendants.'
The beast brings down his sword, and she screams--]