Looker

"You dress up as any superhero you want. Supergirl. Looker, if vampires are more your thing."

- Grace

History
At some point, Looker has become a vampire and was also a superhero, who amassed a certain fandom with people who have vampires as their "thing."

Season 2

 * "The Book of Blood: Chapter Two: The Perdi"

Trivia

 * Much like with Supergirl it is unclear whether Looker is a fictional or real superhero in this universe. She is a real person but is not a superhero.

Behind the scenes

 * In the DC Comics Looker is a superhero with psionic abilities who was also later turned into a vampire.