Midnight Sparkle

"(evil laugh) You were right! I didn't understand magic before... but I do now!!!" - Midnight speaking to The Rainbooms

Midnight Sparkle (voiced by Tara Strong) is Sci-Twi's alter ego and Princess Twilight's dark side who first introduced as the ultimate antagonist in Twilight and Kyle's Adventures of Equestria Girls: Friendship Games.

Trivia:

 * Although Sunset Shimmer saved Sci-Twi from her alter ego, it is known her dark side somehow got infected on her Equestrian counterpart, which her dark side is named as "Midnight Sparkle".
 * Midnight will become Jeffrey and Jaden's enemy in the future crossovers whenever Twilight loses control as the darkness spreads all over of her.