She is one of my favorite ponies, not only because she is a lesbian. I really like her color and her warm character :)

As you know, she is in love with the Magic Crystal and is her old friend. Crystal has known for a long time that her friend is gay, but still does not know that Light is in love with her.

How did Sunset Light get her cutie mark?
She got it quite late, as a teenager. She, like other Pegasi, distributed clouds for the weather. But this was not enough for her and she made a beautiful picture of the clouds in the sky. Because of the sun, the clouds turned into beautiful red, coral and pink colors, which matches her color. So she received her insignia and, until her death, she continued to delight the inhabitants with beautiful landscapes in the evenings and mornings.