Prince Blueblood

Prince Blueblood is a unicorn pony who appears in the Grand Galloping Gala as the object of Rarity's affections.

History
He first appears in Rarity's fantasy in The Ticket Master, where she explains he is the nephew of Princess Celestia; in her dream, they swiftly fall in love and marry. Prince Blueblood appears outwardly the same in The Best Night Ever, where Rarity expects him to court her as he did in her dream, but he is too self-centered. Rarity expects Prince Blueblood to give her a rose, but he takes it for himself; he brings a cushion only for himself to sit in the castle's yard, leaving Rarity without a comfortable seat; she expects Blueblood to throw his coat over a puddle so her shoes won't get dirty, but he coerces to throw her shawl; he expects her to pay for his dining; and he generally ignores her wants, and patronizes "common ponies". He even goes as far as using Rarity as a pony shield from getting cake all over his clothes.

Through the entire Grand Galloping Gala, Rarity tries to make pleasant company with Blueblood, but his self-centered nature drives her to the point of extreme irritation. After he uses her to shield himself from an incoming cake, Rarity finally snaps and tells him off as the most "uncharming Prince she's ever met", and shakes the cake all over him in retaliation. After complete control is lost of the Gala, Rarity and her friends leave the scene, but she loses her glass slipper when running down a set of stairs. Pinkie Pie suggests that now her prince is sure to find her; panic-stricken at the thought, Rarity crushes the slipper and runs off.

Trivia

 * The show's creator stated that Prince Blueblood's title was initially supposed to be 'Duke', and that he's the "great great great great great great great great great great great (and probably even more greats) nephew on Celestia's and Luna's mother's side, about 52 times removed, roughly speaking."
 * His name, Blueblood, is an English Idiom for "nobility" or being of noble birth or descent. It has been recorded since 1834 and comes from the spanish words sangre azul, describing Spanish royal families said to be descendants of the Visigoths.
 * He was voice by Trevor Duvall