Why the Latest 'Flash' and 'Arrow' Crossover Is About to Become Legendary

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It’s that time of year again! The Arrow and The Flash crossover is here, and it’s bigger than ever.

The CW’s anticipated two-night event kicks off on Tuesday’s Flash when Barry Allen (Grant Gustin) seeks the help of Oliver Queen (Stephen Amell) and Team Arrow after the villainous immortal Vandal Savage (Casper Crump) becomes more than they can handle. Vandal’s unwelcomed presence in Central and Star Cities isn’t without reason: The 4,000-year-old soul is dead set on going after winged warriors Hawkgirl (Ciara Renee) and Hawkman (Falk Hentschel), with whom his history is fraught with tension.

While last year’s Arrow and Flash crossover was less a two-parter, that’s simply not the case this time around. Miss the first or second hour, regardless of which show you have an affinity to, and you’ll be having a serious case of FOMO.

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That’s all by design, due in large part to the upcoming midseason spinoff DC’s Legends of Tomorrow.

“This time around, given the success that we’ve had previously and how people are viewing this as much more of a collective, shared universe, we felt emboldened to really have a two-hour true event with one story and one villain and one storyline,” executive producer Andrew Kreisberg says.

“Story-wise, it was appealing to us to try and do something different than we had done previously,” executive producer Greg Berlanti adds. “We wanted to challenge ourselves to see if we really had two hours’ worth of storytelling and could follow everybody all the way through. What would that look and feel like?”

In a word: epic.

Nearly all of Star City and Central City’s masked heroes play integral roles in the explosive two-hour jaunt, which sets the table for Legends with the origins of Vandal Savage, Hawkgirl and Hawkman -- though not everyone from Legends comes along for the ride.

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“We wanted to have some [characters] but not all in it,” Berlanti explains, “so it also felt right that we would use the characters that we hadn’t introduced on the individual series yet -- with the exception of Rip Hunter, who we saved for the pilot of Legends.

Flash fans have already begun peeling back the layers on Hawkgirl, aka Kendra Saunders, but it’s Hawkman, aka Carter Hall, who they’ll see in action for the very first time. For Hentschel, who auditioned for various parts on Arrow and The Flash before snagging this one, the role was meant to be even if it took a long time coming.

“My name Falk, literally means hawk in German. And not to be too serendipitous, it was like, ‘OK, this makes sense,’” the East Germany native tells ET. “I saw the character description and showed it to a friend and they said, ‘Oh, that’s sort of you!’ I’m sort of hippie-dippy and into reincarnation and all of that. It all fell together and felt very natural. It was right.”

Hawkman, like Vandal Savage, is centuries old and he’s lived -- and died -- through more than 200 lifetimes. Fated to be with Hawkgirl, the winged hero does just about anything for his soulmate, including an entrance that can only be described as “brash.”

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“He’s just like, ‘Here I am and this is what I do,’” Hentschel says of his alter ego’s memorable arrival. “Before, he’s never encountered any opposition -- this time it’s Flash and Arrow. I love this girl and she loves me, so [get] out of the way.”

“At first, Oliver, Barry and Carter don’t get along because they think he’s a dangerous person who wants to harm Kendra. Then, they start to warm up to him. If you don’t know him and don’t know that he’s right, he sounds crazy.” Hentschel adds.

Playing one half of a couple who’s destined to be soulmates for the rest of time is a daunting task, but one Hentschel is intrigued by.

“You get to see that really play out. In movies, you usually go, ‘This is my soulmate,’ and then you get the Notebook ending and it all works perfectly. But these guys have done it,” Hentschel says. “They’ve done it 206 times and I’m sure they’ve gone through all scenarios. They’ve lived together and probably had 10 lifetimes of happy love, but is it still that intense? There’s potential for these two characters to really get into it and mess around with that subject.”

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It helps that the chemistry between Hentschel and Renee, with whom he shares many of his scenes in the crossover, is undeniable. “All the good things you can say about a person, I will say about her,” he marvels. “We had a natural liking for one another.”

That mutual admiration extends to the Arrow, Flash and Legends casts. A former professional dancer, Hentschel shared that he and members of the cast engaged in an intense dance-off during downtime while filming the crossover.

“Grant Gustin made me laugh a lot. We had a tap [dance]-off. I wouldn’t even say it was a tap-off, I would just say that he annihilated me and I tried to defend myself and lost,” Hentschel concedes, chuckling at the thought. “Next time, I’m going to challenge him in hop-hop -- let’s see if he still does well. I’ll get him back in a different style.”

Producers have been up front about using the early part of Arrow and The Flash's current seasons to lay the groundwork for Legends, and the crossover event is no different. Once the spinoff launches next year, however, it’s back to business as usual for the Green Arrow and scarlet speedster.

“Once Legends is born in January, there’s really no intersection on the other shows,” Berlanti says. “Legends is its own wacky, crazy kind of thing that allows for some fun surprises, in terms of who may visit and how because they’re flying through the timeline, but not on Arrow or Flash.”

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and Arrow fans, are you excited about the two-night event? Share your comments by using the #ETnow hashtag on Twitter! 

Part one of The Flash-Arrow crossover airs Tuesday at 8 p.m. ET/PT, with part two following on Wednesday at 8 p.m. ET/PT on The CW.