In the DC Comics, Leonard Snart was raised by an abusive father before turning to a life of crime. Leonard invented a powerful freeze ray gun that disabled his enemies, and founded the group of villains known as The Rogues.
Executive producer Greg Berlanti revealed that the character will debut in the fourth episode, which will provide an origin story for both Captain Cold and The Rogues.
"We'll be seeing his origin and the origin of the Rogues."
In related news, TV Guide reports that Episode 8 of The Flash will be a two-hour crossover event with Arrow. Here's what executive producer Andrew Kreisberg had to say after the TCA panel, confirming the crossover event.
"Episodes 8 of both shows, Arrow and Flash, are going to be a two-hour crossover event. [Also], in Episode 4, Felicity [Emily Bett Rickards] is going to come to The Flash."
The Flash, which executive producer Geoff Johns hailed as, "the most faithful DC adaptation ever," has hinted at the arrival of Gorilla Grodd, whose presence is teased in the pilot when an empty cage is shown.
"Obviously that Easter egg means the world to us, Dawn of the Planet of the Apes is out and hopefully they're doing the R&D for us so that one day we can see exactly what jumped out of that cage."
We reported last week that Robbie Amell will appear as one half of Firestorm, Ronnie Raymond, with Greg Berlanti confirming that the actor will appear in the third episode. Ronnie Raymond is just one half of Firestorm, who was created when Ronnie and Nobel Prize winning physicist Martin Stein were caught in a nuclear storm that fused them both into one body. While Martin Stein has not been cast yet, Greg Berlanti revealed that he will definitely show up at some point during Season 1.
"I think as we evolve Firestorm, you'll definitely meet Stein. We actually had him in a version of the pilot at one point on the train with Barry when he was coming back from Starling."
The producers also hinted that the red leather suit worn by Barry Allen (Grant Gustin) will be altered over time, thanks to his support team at S.T.A.R. Labs.
When asked if he enjoyed running as a child, Grant Gustin had this to say.
"I hated running. I quit soccer because I thought it was ridiculous going back and forth."
The Flash will debut on Tuesday, October 7 at 8 PM ET, but for those who are attending Comic-Con 2014, the entire pilot will be shown during Preview Night, Wednesday, July 23.