Shout out to Ink Rose who inspired Cherish’s back story, please see the link I have shared.
https://youtu.be/WFv1pcJe00U?t=9m28s

Cherish is the older sister of Princess Celestia and Princess Luna. Her story begins back when Celestia and Luna where just little foals.
Cherish goes to investigate a cloud of black smoke and leaves her 2 sisters in a safe place. What she finds is a large fire breathing dragon destroying a village near the castle. Cherish fights the dragon to protect the ponies of the village and more importantly to her, her sisters.
After the fight with the dragon Cherish ended up in a crystal tomb, and would remain their for several thousand years, till just a few days after the Crystal Empires return. Her crystal tomb would open and a colt named Macintosh finds her and helps her to safety.