Crystal Dawn

Crystal Dawn is the third born daughter of Twilight Sparkle and the main "protagonist" (more of an anti-hero) of Part Three and secondary protagonist of Part Four in My Little Pony: Generations Of Harmony

Personality
Crystal was originally a happy-go-lucky pony having fun with her friends until Bengilum had her friends turn against her and she became bitter and resentful but thanks to Twilight Sparkle she was brought back to friendship

Appearance
Crystal Dawn is a earth pony with a cream coat and blue and white mane she wears purple sunglasses a pink skirt she has The Friendship Heart in a golden necklace she also has the mark of Bengilum on her front right hoof

Depiction in Generations of Harmony
Before Part Three Crystal was a bright cheerful pony but to get her on his side Bengilum mind-controlled Crystal’s friends to turn against her and make her turn against friendship

In Darkness Crystal releases Bengilum to get revenge on Twilight for (unintentionally) neglecting her after her friends left and joins him running away from the castle after he was defeated

She later meets the other followers namely Mal Ice and Blizzard Moon but she later causes Blizzard to leave using her potion to erase her mark. Later Blizzard gives Crystal a vial of the potion and begins to consider leaving Bengilum

During Out of The Dark Crystal finally goes back to friendship and uses The Friendship Heart to permanently banish Bengilum

In For Generations To Come She tries to keep Equestria safe from Nightshade Bloom and the Forces of Shadow while Twilight Twinkle and Sprinkle try and escape the spirit world after the final battle she becomes the co-captain of the guard

Trivia

 * She along with Nightshade Bloom are the only two Anti-heroes in the series
 * Crystal is the only good daughter of Twilight (in Part Four) to be in Equestria before the final battle