The superhero world of The CW's DC Comics-based hits "Arrow" and "The Flash" has gotten pretty crowded in the past year -- so crowded that many of the marquee characters that populate the "Arrow"-verse will branch out into their own show in early 2016, "DC's Legends of Tomorrow."

The spinoff will star The Atom (Brandon Routh), Captain Cold (Wentworth Miller), Heat Wave (Dominic Purcell), White Canary/Sara Lance (Caity Lotz), Firestorm (Victor Garber and Franz Drameh), Hawkgirl (Ciara Renee) and Hawkman (Falk Hentschel), gathered together at the behest of Rip Hunter, Time Master (Arthur Darvill). Immortal villain Vandal Savage (Casper Crump) will be the main antagonist of the show's first season, with the team traveling through time and visiting the "greatest hits of the 20th century," as showrunner Phil Klemmer described it; pivotal moments in history where Savage played a key (and sinister) role.

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Last month at New York Comic Con, Klemmer talked to a small group of reporters including CBR News about the "kind of nuts" upcoming "Flash" and "Arrow" crossover -- taking place on both shows in the first week of December -- that will introduce the "Legends" concept, how a couple of Rogues like Captain Cold and Heat Wave fit in (or don't) within the team and the "human-scale story" at the heart of the time-spanning adventure series.

What can you tease about how "The Flash" and "Arrow" are going to introduce "Legends of Tomorrow"?

Phil Klemmer: What we've planned is kind of nuts. There were crossover episodes last season, and now we've doubled-down on the notion of trying to integrate the worlds of the three shows. It's such an awesome idea on paper, but logistically, when you try to figure out what it means for these poor actors trying to appear on three shows at once -- time travel is something that makes your head want to explode, but the idea of trying to find how to make the worlds of all three shows coordinate? It probably will kill us. Or kill one of the actors. [Laughs]

But if it works, I think it could be one of the coolest things. It's not happening anywhere on television, and it seems like it really enriches the world of all of the shows, when you have people crossing through the background; the sort of "Rosencrantz and Guildenstern are Dead" of realizing, oh man, all of a sudden, these places feel real. If somebody was on another show, and then they're on their show, that lends the luster and combines it.

What do you like about the mix of characters on this show? It's an eclectic, kind of random cast in that this is a team that was never a group that was in a comic together; it's characters from all over DC put together for the first time.

And I really like how we justify that in the pilot, although I don't want to give away the secret. To me, those are the sort of heroes that really interest me -- the underdog versions. Superman's awesome, but he doesn't have problems that I can relate to. I like the f-up heroes, and the sort of crooked heroes, and to combine them and watch them bump up against each other -- that's a recipe for TV that's fun to write. I came up writing shows that are based on flawed people, like "Veronica Mars" and "Chuck." That's what I'm good at. Those are the kinds of people I relate to.

What can you share about the villain of the first season, Vandal Savage?

With Vandal, with any villain, the trick is always to find somebody commensurately evil or formidable. We have an ensemble of eight-plus heroes -- you have to come up with a version of the antichrist if you want it to feel like it's anywhere close to being an even challenge between the black hats and the white hats; although in truth most of our guys are sort of gray hats. Coming up with an immortal seemed like the only way that we could have a bad guy who matched our team.

Will there be more female superheroes introduced to the team?

I was just thinking about that. I was doing the math -- it does feel like we have a need for some double-X chromosome ass-kickery, although I will say that the two women we do have can certainly hold their own, and make up for their numbers with their strength of personality and pure strength.

Who's available to join? Obviously not Supergirl or characters on "Gotham."

It's true. You have to go deep into the catalogue. But one of the virtues of being able to travel through time is, we can find mortals who would be part of our cause, and maybe we can find superheroes from different incarnations, because we're able to go back in time.

Curious to hear more about how Captain Cold and Heat Wave fit in.

Not very well. [Laughs]

They're bad guys -- maybe not the worst guys we've seen on these shows, but they're not heroic. is it an ongoing concern as to whether or not they can be trusted?

It absolutely is, and those suspicions are certainly borne out. But I can really relate to their badness. On our show, as opposed to "Flash" where they came in as guest stars, we get to live with them, and really get to get under their psychopathology. Hopefully people come away kind of feeling for these guys. I find their Butch and Sundance-style friendship -- they don't believe in much, but they believe in each other -- totally heartwarming.

Will the Lazarus Pit continue to affect Sara throughout the season?

Her journey's really interesting, because it really is a struggle for her to reclaim her humanity. We were just talking about Leonard (Captain Cold) and Rory (Heart Wave) -- those guys have lost their humanity by being villains, but she's had hers stripped from her. For her, it's about trying to find human connection. It's a very human-scale story. It's an action, superhero series, but I think it should be relatable even for people who don't get into people with costumes and powers and the like.

In terms of scale, "Arrow" is very urban and "Flash" is mostly grounded in one location -- how different is this?

This is real different. It takes place on a spaceship that travels through time, and arrives in different eras and locations. It is sort of divided into chapters that are serialized. It's not episodic, bad guy of the week, it is two or three or four episodes in a time period.

We want to do the greatest hits of the 20th century. Without giving away spoilers, it's like, if you had a time machine, where would you go? Where would you intervene? Trying to imagine Vandal Savage as the devil in "Sympathy for the Devil" -- imagining that this guy's been going through history, dipping his fingers in human events, and steering the course of history for his own evil purposes.

That's the fun of our show; trying to find him and intercept him at these points in history where the balance seemed tipped, whether that's Cold War, nuclear annihilation or World War II fascism, you name it. If bad s-h-star-star was happening, Vandal was there. The fun of our show is encountering him in these iconic, 20th century crucible moments.

"DC's Legends of Tomorrow" debuts in 2016 on The CW.