Pinkie Pie:

Pinkie was originally a normal party pony until she heard that Celestia turned into a tyrant and Twilight's magic got stolen, she started to become depressed over time and stopped making parties. Pinkie now likes to be called Pinkamena.

Rarity:

Rarity was once a pony who loved making dresses for ponies until the world got more depressing and no pony would ever come to get any dresses so she started to become a bit depressed and she loved getting dirty but she still was happy to have friends by her side.

Rainbow Dash:

Rainbow loved to fly fast but that all changed when Celestia became a tyrant and she couldn't fly fast anymore because it was now illegal, Rainbow got so mad that she went to Canterlot and tried to hurt Celestia but Rainbow Dash got hurt instead then she flew off because she saw how powerful Celestia was now.

Applejack:

Applejack was a kind and honest country pony who loved to help her family but as soon Celestia became a tyrant, she became really shy among ponies; including her family.

Fluttershy:

Fluttershy was kind, sweet and gentle to everypony until Celestia became a tyrant and she started to pick up a habit to not be shy anymore and Fluttershy really loved to make her animal friends some dresses to wear.