Both villains will be introduced in the first episode, acting opposite star Grant Gustin as Dr. Barry Allen (aka The Flash). The series revolves around a Central City assistant police forensics investigator who arrives in Arrow's Starling city to look into a series of unexplained robberies that have a connection to his past. He also gains super speed.
Rick Cosnett will play Detective Eddie Thawne, a transfer to the Central City Police Department whose past is a mystery and who harbors a dark secret. In the comics, he is able to replicate the accident that gave Barry Allen his powers, himself gaining super-human speed to become Reverse-Flash.
Danielle Panabaker is Caitlin Snow, a highly intelligent bioengineering expert who lost her fiancé during an explosion at S.T.A.R. Labs. In the comics, Snow turns into Killer Frost after a lab incident finds her body fusing with an engine's coolant system, as her biological makeup merges with ice. As a result, she becomes a vampiric villain who craves heat, and must kill to feed on body warmth.
While Grant Gustin has already appeared on Arrow, Barry Allen's transformation into The Flash was originally meant to be a backdoor pilot included as part of that hit CW show's Season 2 run. Now, The Flash is getting a regular pilot, which indicates that The CW is seriously considering a series pick-up for Fall 2014.