Cadence the crystal princess

Everyone knows that Cadence is the Crystal Princess but there was whole royal family. King Sombra wasn't fighting to keep his empire but instead to keep his wife safe. His PREGNANT wife in fact. And be live it or not Cadence is Sombra's daughter. Don't be live me? This quote from the show proves my whole point.
Bright Smile: Behold! The Crystal Princess!

Why would Bright Smile (Yes that is the ponies name. I got this quote from the transcript from the episode.) call Cadence the Crystal princess. Well my dear readers I can tell you how. A year before the events that led to Sombra's defeat the king met his bride to be. She was a singer named Crystal Rose who had come to sing at the Empire. He only saw her as a way to keep his kingdom and started to court and seduce her. As time when on he slowly fell in love with her and soon they where married. Nine months later and the royal couple where expecting a child any day know. Then the day that the foal was due Celestia and Luna attacked. They belived that Crystal Rose was being held against her will from an anonymous message they had received and where determined to free her. Sombra refused to let his wife leave him causing a war between both countries. Sombra sealed his wife in a room with a magical spell that would protect her no matter what. As King Sombra and the princesses clashed Crystal Rose went into labor. Just as the battle drew to a close and Sombra was defeated she gave birth to a pink Pegasus she named Cadence. (lets just say that its the same reason the cakes gave for their children.) With his last moments of life Sombra cast a curse on the Empire that caused it to disappear and the same curse activated the spell that would protect Crystal. It sealed her in a mirror at the top of a tall tower. Crystal used the magic of her love for her daughter to deposit her on the doorstep on a unicorn couple in Canterlot.

well I hope you enjoyed this little headcanon of mine. This story is told in detail in my story the crystal queen.