Naomi was a high-ranking angel charged with making rebellious angels obedient once more and extracting information from them. Following the slaughter of Raphael's followers at Castiel's hand, Naomi headed one of the many factions of angels vying for leadership of Heaven. She saved Castiel from Purgatory to brainwash him into being her unwitting agent in Season 8. Upon learning of Metatron's plan, she attempted to stop the scribe, only to be killed by him instead.
Naomi's character was cunning and very important to season 8th story line. She is one of the bad guys of the season. Below I have pulled up some styles to dress as her for cosplay. You know that pretty much all characters from SPN is easy to cosplay as.