She said yes. Discord was still partially in shock that this mare agreed to stay with him forever, even though it meant giving up all that she loved to save her friend. Even after seeing his hideousness and experiencing his cruelty. Her fright was expected and understandable, but it had pierced his heart. Her trembling assent though, he had not seen coming. He thought that she would just leg it, get out and go as far away as possible, leaving her friend to her fate, and leaving him without any hope of finding true love.
Yet, she had agreed. Despite his amazement, he agreed to her side of the bargain. She had the courage to take her friend's place as prisoner. Discord just couldn't understand it, all this friendship stuff, it just went over his head. There was nothing particularly special about this little filly, who seemed quite emotional, selfish and nervous. Plus, she didn't have a Cutie Mark. Anyway, what this mare saw in him to save her friend was behind him. Had she had chosen to leave, he would have told her to never return no matter what and to tell nopony what happened, although she too was a trespasser. He sighed. One minute he was all nice to the little filly and the next, her life was in the balance. What was wrong with him?
Discord was still pondering the new state of affairs as he stalked back to the West Wing. He slammed the door behind him and trudged miserably to his chest of drawers. On top of it was his key to the outside world, the Magic Mirror. He thought for a minute. Then, he knew what he wanted.
'Show me the mare,' He commanded in a rough voice.
With a flash of light, the mirror revealed Fluttershy lying on her bed, still weeping, though not as hysterically as before. Discord half smiled. Even in great distress, she still looked so sweet. Maybe she was beginning to get to him. But wait, remember what Luna had warned him, to not judge by appearances, that there's more to a pony, not just love at first sight.
Discord groaned and the mirror down onto a conviently placed couch. All this friendship stuff was just too much for him to think about, it's be best to just sleep on it. And that's what he did.