Included story:
 
Long before King Sombra sacrificed himself to save his and Celestia’s homelands, he had a feeling deep down that something would happen to permanently separate him from his love. He also knew that Celestia wanted to have children with him and live happily ever after. So, to prepare for the occasion, he froze some of his sperm and gave them to Celestia for if she ever wanted to bear his child. At the time, she was too blinded by love to realize why he was giving her such a gift, but she accepted it anyway.  
Years later, Celestia found the frozen sperm stored away in the castle. At the time, she was feeling lonely without somepony to love. After thinking it over for a while, she decided she was ready to have a child now before they expired.  
While most of the sperm were damaged by time and circumstances, there was one that was left completely unscathed. Celestia, with the help of her private doctors, inserted it into herself and hoped for the best. To her relief, she successfully became pregnant with few complications.  
Almost a year later, Celestia gave birth to her son, Velvet Shade. It was a bittersweet occasion; she was happy to have her baby, but it saddened her knowing that he would never get to know his father.  
Celestia raised Velvet Shade the best she could as a single parent, with help from Luna. She gave him the unconditional love of a mother and instilled values of friendship and harmony into him, just as Sombra would have wanted. Throughout all this, Celestia held a sadness within her that would not go away. Velvet served as a constant reminder of the love she lost and it pained her to think that both she and her son would never see Sombra again. While Celestia tried her best to hide these feelings, both Velvet Shade and Luna could tell something was off.  
One day, as he was exploring the castle out of boredom, Velvet Shade found something that would change his life. He discovered underground tunnels that held artifacts and mementos of the past. Among all the dusty old books and historical documents, he found pictures of a strangely familiar stallion. Some of these pictures even included his mother. Along with the pictures he found letters to a pony named Sombra, written by his mother.  
It was at that moment that Luna found her nephew curled up sobbing on the ground. Knowing that he had questions that he needed answered, she took him to Celestia and demanded that she come clean. Celestia explained the whole situation with King Sombra to her son, and the two reconciled. Deep inside, Velvet Shade vowed to reunite his parents no matter what it took.  
Ever since, Celestia and Velvet have been living a pretty nice life together. Celestia still feels bittersweet whenever she thinks of Sombra, but she has been able to move on enough to have a real relationship with her son. Meanwhile, Velvet has been looking for ways to reunite his parents and see his mom truly happy. Someday, he hopes, their family will be whole again.