Once upon a time, there was a Princess.  
She was a beautiful Princess, her coat was like diamonds glittering in the Sun, and her eyes sparkled even in darkness. She was the envy of every mare, but beloved by all. For this Princess, was the Crystal Princess, and she ruled her Empire with a fair and kind hoof.
 
Once upon a time, there was a King.  
He was the Unicorn King, with a dark coat and tall stature that towered over most. Though he intimidated many he met, he was respected by his subjects and loved by his wife. Life couldnt have been happier for him and his Queen, especially with a Princess of their own on the way.
 
The Crystal Princess was adored by all her subjects, nopony thought any ill-will of her, for she was there for any of them, no matter who. But the Princess had a secret.
 
The Unicorn King ruled his Kingdom as best he could so that their unborn child could live in a world the King and Queen would be proud to call their own. But tragedy befell them.
 
Nopony knew, but the Princess had a selfish heart. She loved her subjects, but loved herself more. She treated them with fairness and kindness, only to hear the words of admiration they spouted out to her every day.
 
Nopony could have known, but the Unicorn Queen did not survive the Princesss birth. The loss devastated the Kingdom, everyone was left distraught. But none were more upset, or more heartbroken, than the King.
 
She wanted nothing more, than to be worshiped. She put her ego above her Empire.
 
He wanted nothing more, than his wife back. But, he put his Kingdom above his sorrow.
 
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Rest of the story can be found here: http://torusthescribe.deviantart.com/art/Daughter-of-the-Unicorn-King-462677230