WMG / Sunshine and Fire

The Elements of Harmony in this world require Daylight Sparkle

What else would provoke the despair of Twilight, than to learn that a mortal enemy is needed to defeat the ultimate evil? It would be shocking. It would make sense given the "other universe" component, and it might turn into a facinating story arc akin to something from Avatar: The Last Airbender in discussing what makes Daylight tick, and how can "the collaborator" turn into an ally?