This story is a sequel to The Return of the Shadows

Princess Celestia sends King Sombra to Ponyville to learn about friendship with Twilight and her friends.
But days passed, and between Sombra and Twilight something else grows.

Upon her first use of darkness its taste lingered within her mind, creating an ever growing thirst and revealing her true desires. With her recent elevation to an alicorn and princess she begins to find her desire for power insatiable. Small seemingly inconsequential steps grow into giant leaps, pushing her senses of morality and reason.

Besides, doesn't the ends justify the means? For a queen can accomplish so much more than a princess....

********
Special thanks to Omny87 on DA for the inspiration.
FEATURED: 7/1/2014 THANK YOU ALL!