Celestia and Luna were born as earth pony foals in a dangerous world. They must rise from nothing to become the princess we know, upsetting chiefs, gods, and the very forces of nature in the balance.
Twilight has spent her adult life keeping Equestria safe. While her friends found careers, family, and love, she has spent her time searching for ways to defend them all. Resentment now rules her heart, and somepony has to get through to her.
One day, something terrible and unexpected happens to Celestia, and time is lost to the sands. She'll find that her entire world is gone and that almost everything she knew and loved has disappeared...forever.
Twilight is unable to control her powers during the entrance exam to the School for Talented Unicorns, and in order to reduce the damage caused by her power surges, Celestia shrinks her down until she would later learn how to control her powers.
A human soul is stuffed into King Sombra's body. Having no idea what's going on, and thinking he is in some kind of coma, he just casually strolls into the Crystal Empire.