From source:

Discord and Celestia Assurdita is a child that can best be labeled as having a Chiaroscoro-esque personality. She is constantly battling the light and darkness in her but really never belongs in one place, ex. being Equestria or Discordia.

Not long after Assurdita is made princess of her daddies land does she sense her emptyness and still doesn’t know who she is (mostly stemming from her blank flank). This gets her mother and father into a cross-continent debate.

Celestia thinks that Assurdita should grow up to be like her and raise the sun, while Discord wants Assurdita to be like him and live without a cutie mark. Without thinking of really what their child needs and more what they want, both parents are completely shocked when Assurdita’s cutie mark appeared, and was a storm cloud.

This meant that she controlled weather of all things and had nothing to do with either of their professions. Instead ickle Assurdita grew up to be a traveling spirit controlling storms and bringing balance to the lands that lay between Equestria and Discordia. She also controls the benefits and loses of war, hence why some ponies, dragons, anon monsters have dubbed her the “Athena alicorn”. Even though she is the witty, and rightious spirit of balance she still is very true to her father and his country. Her usual introduction being “I am Princess Assurdita of Discordia.”