“We’re incorporating almost everything from the mythology into it and have added a whole new backstory” with the S.T.A.R. Labs particle accelerator, Geoff Johns, CEO of DC Entertainment, said today during the panel for the new CW series. The series, starring Grant Gustin as Barry Allen/The Flash, is a spinoff of CW’s Arrow.

"Resident Evil: Afterlife" Japan Press ConferenceThe producers also announced today that Wentworth Miller will guest star on the series as Leonard Snart, aka Captain Cold. The series premieres October 7 in the Tuesday 8 PM slot.

Johns said “the most faithful DC Comic adaption ever” includes using as many characters from the comic series as possible. He appeared on the panel with executive producers Greg Berlanti and Andrew Kreisberg and cast members.

One change that does not reflect the comic book:  The characters of Iris West (played by Candice Patton) and Detective Joe West (Jesse L. Martin) are portrayed by black actors.  In keeping with a TCA dominated by talk of network shows’ diversity, Johns said producers wanted Flash to be more reflective of the world we live in. “If you watch Arrow, there’s a great deal of diversity that is key to Arrow’s success,” he said.

The panelists also talked about next week’s Comic-Con and its importance to launching a show to comic book fans. They called it a “pilgrimage” and joked: “I don’t think there’s a Grey’s Anatomy Convention.” The Flash will premiere its pilot on Wednesday at the San Diego convention, with the CW, Fox and NBC set to show off all the DC series fare — Arrow, Flash, Gotham and Constantine — during a Hall H presentation Saturday night.