Artist’s description from DA:

“Alternate Gender Counterparts of Heroes” is my new project! Here, characters switch roles with their soul mates (mares with stallions and stallions with mares).

Flash Sentry is the Alternate Gender Counterpart of Twilight Sparkle (so I made him a unicorn). He is the most faithfil student of King Sombra (he is the AGC of Princess Celestia), who loves to explore the secrets of magic and read books. He was sent to Ponyville to learn Magic of Friendship. He represents The Element of Magic.

Dim Sum is the Alternate Gender Counterpart of Spike. She’s loyal assistant of Flesh Sentry. She writes letters to King Sombra.