Twilight Sparkle married her own clone (as far as others were concerned) and slowly began to retreat into her castle. Ever since Celestia announced her retirement, she had began to grow more manic. Nearly having panic attacks daily, not being able to trust or delegate anything to anyone other than her friends. Even then, their contact was limited. Twilight began to speak with their alternate reality-self, slowly growing a relationship.

After the two Wed (will expand on their relationship later) she began work on their child. While two mares could naturally have children in Equestria, she had always been fascinated by biology and children in general… At least, in concept.

Twilight Zone is a chimera, having absorbed their twin in the womb. This was one of the few things that stuck out to Twilight and had her keep the child. While the alternate Twi was pregnant, our Princess began spiralling down. She fell back on a old habit, studying everything. Which brought up the topic of soul magic, organs, the amount of stress that could be put on the body and mind until it crumbled. She rationalized this as a need for complete control, if she witnessed these horrors she could prevent them from happening. But internally she knew she had a sick fascination with the idea of taking a creature apart to see how it ticked.

This effected how she treated her child. Zone was an exceptionally quiet and morbid child that dutifully listened to her mothers. Almost robotic, most likely selectively mute. She waits and listens to conversations, her photographic memory recording everything to tuck it away for further use. Zone has an uncontrollable need for perfection in everything in her life and doesn’t tolerate others. She doesn’t share, doesn’t care, and will do anything within her power to get what she wants…

(This twilight based on The Experiments of Twilight Sparkle!)