"When we first meet Barry Allen, he's just a forensic scientist … an ordinary man," Kreisberg said, stressing the character, like Amell's vigilante, will be grounded in reality and as realistic as possible. The first two episodes will see the character in Queen's home of Starling City, with the 20th providing a window to see Barry in The Flash's world.
"Part of the fun for the audience … is to see how we view our Arrow take on the Flash legacy," Kreisberg said. "Some of it will feel very familiar to DC Comics, some of it hopefully will feel different, fresh and exciting. The same way we approached Arrow is the same way we're approaching Barry."
One of the things that grounds CW's Arrow is the fact that the series isn't about individuals with superpowers -- with The Flash a clear violation of that. Producers noted that they'll handle the introduction of Barry's superspeed in a way that isn't commonplace. "There will be extraordinary events in the world and the characters will react in the same way," Kreisberg noted.
"The fact he has superpowers, there's something more relatable about Barry among the Big Seven of the Justice League," he added. "He got his powers by accident; he's not a god, he's not an alien … his reactions to that feel very … human and grounded."
Since Flash is a backdoor pilot episode of Arrow, the character will mix it up with Oliver -- providing a stark contrast between the two heroes.
"Oliver Queen is a very dark and tortured soul, and Barry is not," Kreisberg said, noting he will have a profound impact on Oliver, Diggle and Felicity. "He's a great character who is going to affect all of our characters' lives. It will be fun … to see these two characters together because they have two different worlds."
Added Johns: "We're also exploring a very personal story for Barry -- life as a forensic scientist and the people around him, the tragedies and how he deals with them -- in a very different way than Oliver Queen. The intention, they noted, will be to add to Arrow instead of stripping away characters from the series should the spinoff move forward, meaning it's likely the residents of Starling City will remain there.
Johns reiterated that the Justice League member will be seen as The Flash -- complete with his trademark red costume and not a poor imitation. Added Kreisberg: "No sweat suits or strange code names; he will be The Flash."
Producers haven't yet figured out how they plan to depict the Flash's lightning speed but Johns insisted it won't just be the standard "blurring around."
"It's not what people expect," Kreisberg said. "We want to do something fresh, new and exciting and give people a real cinematic experience the same way we did with Arrow."