Fortunately in this reality she survived thanks to the intervention of Nyx from the Contacts Universe approx 20 years ago.
Having been raised on a farm (after Nightmare Moon her mother was forced to give her away for her own protection) with an Apple Family (not the Applejack family but related one way or the other).
Because of this she is considered an "Apple" (Dawn Apple) and therefore has a slight Texan accent.
Dawn has no idea what happened to her mother.
Having spend so little time with her biological mother and being raised by Earth ponies she barely knows any magic and she's a poor flyer.
She also has a docile and passive temperament of Fluttershy.
Because she is chosen to be one of the Nyx Alicorns (yes she is still a sort of alternate reality Nyx even though she doesn't have a black coat, her heart in her cutiemark has the same color scheme of the shield as all the other Nyxes making "Contacts" Nyx suggest that the heart may be a SHIELD shaped as a heart) to take the fight to Nemesis, Nyx Sparkle has to make from this docile creature a formidable warrior princess in record time.
Her Cutiemark is inspired by the story.
Being Dawn she is somewhere between day and night. And having the ability to change the heart of Nightmare Moon from Hatred to Love during her pregnancy suggests that she has a special talent similar to Cadence.
(If you can come up with a better cutiemark design feel free...)
- Nyx Petite Pie: Emblem of Dark Magic (Representing Earth Ponies)
- Nyx "Zeta" Sparkle: Emblem of Neutral Magic (Representing Pegasi Ponies)
- Dawn Apple: Emblem of Light Magic (Representing Unicorn Ponies and the element of magic, however being raised by Earth Ponies she knows barely any)
- Contacts Nyx: The Gate Keeper.
Fortunately being raised on a farm and being worked like a horse she's physically tough as nails.