Starlight Glimmer

Starlight Glimmer is the main antagonist of the Season 5 Premiere and Finale. She is the leader of Our Town. In the Season 5-Finale, it is revealed that she escapes the cave and used a time-travel spell. She makes cameo appearances in "Amending Fences" and "What About Discord?".

Appearance
She has a darker purple mixed with a lighter purple in her mane. Additionally, she has light teal/turquoise highlights. Her coat colour is a pinkish-purple colour.

For her cutie mark, it is shown that it is the Utopian "= sign" cutie mark. Later on in the premiere, it is revealed it is just makeup. Her real cutie mark is a four-pointed star with a blue magic swirl surrounding it.

Personality
As shown in the Season 5-premiere, she has an act of kindness and gracefulness. Later on, it is revealed it is only so that the Mane 6 would allow her to remove their cutie marks. In the finale, it is revealed she was only acting like this because she lost her friend because of his cutie mark.

In "No Second Prances", Starlight has to make a friend. When Twilight objects to her new friend, Trixie Lulamoon, Starlight gets angry and helps Trixie with her show. It is also revealed she has a kind heart to help others, and gets hurt easily when she finds out "Trixie was only using her", which isn't true.

Sunburst
As revealed in the Season 5-finale, Sunburst was Starlight's first and only friend. He helped her on many things, like when she couldn't use magic, Sunburst helped her. Their friendship broke after he got his cutie mark and went off to Canterlot.

In the Season 6 Premiere, she meets Sunburst again and they mend their friendship.

Twilight Sparkle
Starlight took away Twilight's cutie mark in the premiere of Season 5. The second time she appears, she teleports her into the past.

Currently, she is Twilight's pupil and lives in her castle.

Twilight's Friends
She removed Twilight's friends' cutie marks as well. When she reformed, they are still suspicious of her. As revealed in "No Second Prances", they try to help her find a new friend, which fails.

Our Town Civilians
She removed all of the civilians' cutie marks and made them all "equal". When they find out her cutie mark is fake, they get angry and chase her to get the Mane 6's cutie marks back, after they get their cutie marks back.

After she reformed, they forgave her.

Double Diamond brings her the Mane 6's cutie marks in a wagon, which reveals that Double Diamond might be the main assistant to Starlight.

Trixie Lulamoon
Trixie and Starlight became friends in "No Second Prances" when they were in the salon. They had many similarities, thus becoming friends.

Trivia

 * She lived in another village, where she met Sunburst.