My Little Pony Princess Cadance (full name: Princess Mi Amore Cadenza) is the "Princess of Love" and co-ruler of the Crystal Empire. She is a light pink alicorn pony (previously a pegasus) who is the adopted niece of Princess Celestia and Princess Luna, wife to Twilight's older brother Prince Shining Armor and Twilight's sister in law.
She was Twilight's foal sitter when she was younger and remembers that time fondly. Cadance also has the ability to spread love and reduce anger among ponies through her magic. After helping to save the Crystal Empire, Cadance takes her place as "The Crystal Princess", having attained characteristics of crystal ponies. In the novel Twilight Sparkle and the Crystal Heart Spell, her backstory is revealed; she was originally a pegasus orphan who saved an Earth Pony village from a villain wielding a magical necklace. After doing this, she meets Princess Celestia who adopts Cadance as her niece and makes her an alicorn.