To many, Killer Frost is a somewhat popular villain that has appeared in quite a bit of media. She has also managed to do something that very few other super-villains have ever been able to do in the history of comics. Be able to go out of her Super-Heroes shadow and just to do one better, surpass him in popularity.
Spoilers ahead for several series.
Think about it. When you think Joker, Scarecrow, Catwoman, Penguin, Poison Ivy or Bane. You instantly think of Batman. When you think of Lex Luthor or General Zod, you also think of Superman. When you think of Green Goblin, Doc Ock or Venom you think of Spider-Man.
Killer Frost though? Most of the three dozen people I asked about this (and the majority were either comic-book fans or knew about the characters) said Flash, Batman, Superman or that they didn't know. Very few actually said Firestorm. Even with DC's recent attempts to make the connection closer, it hasn't been all that successful.
But the thing is, why is that? Why did Killer Frost get a prominent roles in the DCAU, Young Justice and Injustice while Firestorm got limited to an episode of the Brave and the Bold?
Also why is that only her, Lady Shiva (because who actually remember Richard Dragon), possibly Deathstroke and a few others the only ones to manage such a feat?
P.S. Don't take this as me, insulting the character. I really like Killer Frost and that's why I'm curious.