Twilight Sparkle is the central character of the series, based on the first generation or "G1" unicorn toy Twilight. She is depicted in the movie as a purple unicorn with a pink-streaked indigo mane. She takes charge of the Mane Six during their adventures and helps resolve her friends' differences. She is an intelligent, dutiful, and accomplished scholar with an avid love of learning and studied prowess in unicorn magic such as levitation, teleportation, and the creation of force fields. Director Jayson Thiessen describes her as "kind of a neurotic perfectionist" who has "a touch OCD," prone to suffering from nervous breakdowns when confronted with a problem that goes against her understanding.
Twilight begins the story as the protégée of Princess Celestia, who tasks her with studying the magical properties of friendship in Ponyville and reporting her findings. Twilight resents her assignment in the opening episodes, owing her reclusiveness to her obsession with books, but she comes to form strong friendships with the rest of the Mane Six, which she realizes is key to harnessing the Elements of Harmony. She resides with her assistant Spike and pet owl Owlowiscious (pronounced the same way as Aloysius /æləwɪʃəs/) in Ponyville's Golden Oak Library, where she also serves as town librarian.