Twilight Sentry (nee Sparkle) is the main protagonist of My Little Pony: Friendship is Magic and also one of the seven supporting characters in My Little Pony: The Book of Golden Oak, who made her first debut in season 1 episode 7 "Kunoichi in Peril". She is a pretty unicorn mare who transforms into an Alicorn mare and becomes a princess in Magic Mystery Cure and a pony with a lavender fur coat, purple eyes, and an indigo mane and tail with a pink and purple stripe running through each. She is the younger sister of Shining Armor, the wife of Flash Sentry, the mother of Flashlight, the wife of Flash Sentry, the sister-in-law of Princess Cadance, and the youngest daughter of both Night Light/Mr. Sparkle and Twilight Velvet/Mrs. Sparkle. She also is the paternal aunt of Princess Flurry Heart. She is partnered with Hiro Hamada (Ryan Potter).
She is both a Princess of Friendship and the bearer of the Element of Magic. In the past, she was Celestia's personal student. She lives in her own place in Ponyville, with her baby dragon assistant Spike. In Big Hero 6: Armed Mares, she is serves as Hiro Hamada's partner. In My Little Pony: The Book of Golden Oak, she serves as the acting director of the Golden Oak Library. She has an easy-going nature and a lust for vengeance and battle. She is always searching for an opponent strong enough to defeat her. Before she met Flash Sentry (Vincent Tong), she used to had a relationship with a light brown unicorn stallion named Doughnut Joe (also voiced by Vincent Tong).
- Shining Armor (older brother)
- Princess Cadence (sister-in-law)
- Flashlight (son)
- Flash Sentry (husband)
- Night Light (father)
- Twilight Velvet (mother)
- Flurry Heart (niece)
- Phillip Sentry (father-in-law)
- Mrs. Sentry (mother-in-law)
- (referring to Rita Desjardin) I'm starting to dislike that lady. She's useless.