First Light was a Mary Sue. She's an OC who thought she had everything going for her, even calling herself "Best Pony". But now she knows that she isn't perfect, and she wants to know what her special talent is. She has decided to travel far and wide to find what she is meant to do. She has no cutie mark, but she may yet be able to get it.

The sequel to Say It Ain't Sue! It isn't necessary to read it, but it may help understand the character better.