Princess Cadance

Princess Cadance, also known as Princess Mi Amore Cadenza, is a pink alicorn, niece of Princess Celestia, and wife of Twilight Sparkle's brother Shining Armor. During Twilight's childhood, or fillyhood, she was her foalsitter. She's considered by Twilight to be "the greatest foal-sitter in the history of foal-sitters," as Twilight remembers Cadance as someone who would greet her with a hug, bandage her and wipe her tears when she's hurt and play with her on a swing set. Twilight and Cadance also used to do this little hoof-shake dance together. Cadance eventually became Twilight's sister-in-law after she married Shining Armor. Her special talent is to spread love wherever she goes.

Trivia

 * Cadance will meet Pooh and his friends in Pooh's Adventures of My Little Pony Friendship is Magic.
 * Cadance will reunite with Twilight at the end of season 2 in The FT Squad's Adventures in My Little Pony: Friendship is Magic, but she'll also get a chance to meet the FT Squad.
 * Cadance will also meet Thomas and his friends in Thomas' Adventures of My Little Pony Friendship is Magic - A Canterlot Wedding (Full Movie).
 * Cadance will see Thomas and his friends again and meet Team Robot in Team Robot In My Little Pony: Friendship Is Magic - The Crystal Empire (TMNTSubspace12's Birthday Special).
 * Cadance will meet Dipper, Mabel, and their friends in Dipper & Mabel's Adventures of The Crystal Empire
 * Cadance along with Shining Armor, Princess Celestia and Princess Luna witth make thir brief appearance in Thomas and Twilight Sparkle in Fantasmic (Disneyland Version).
 * Cadance, along with Shining Armor, will join Thomas and Twilight Sparkle's team in Thomas and Twilight Sparkle meets Cinderella.
 * Cadance is also friends with Nanako Dojima and Yukiko Amagi in Yu Narukami and Aigis's adventures of My Little Pony: Friendship is Magic-A Canterlot Wedding.
 * Cadance along with Shining Armor will make their guest appearance in Pooh's Adventures of Thomas and Friends Live on Stage: Thomas Saves the Day, Pooh's Adventures of Stardust and Twilight Sparkle's Adventures of Thomas and Friends: King of the Railway.
 * Cadance along with Shining Armor will join Team Robot In Emerl In Ferngully 2 The Magical Rescue.
 * Cadance is also best friends with Emily.