Starlight Shimmer is a pony I made up. She is basically what I think Shining Armor and Cadance's foal would look like. She takes after Shining Armor in appearance, but has a personality more like Cadance's. Her name is similar to Twilight's (Twilight->Starlight, Sparkle->Shimmer) because I believe Shining Armor loves his sister enough to name his foal after her.