Andrew Kreisberg Reveals His Favorite Part of the Invasion! Crossover

Mainstream superhero comics are often talked about as being testosterone-fueled soap operas: the reason so many people come on board at a young age and stay for the rest of their lives is that they've formed a relationship with the characters.

That's why it's probably not surprising to learn that as much fun as it is to put all the toys together in one box and bang them all together in big, bombastic fight scenes on Arrow, The Flash, and DC's Legends of Tomorrow, what really makes the stories work in the mind of the producers is the relationships between the characters.

"I always love is when Barry is training Wally and he's trying to explain to him how to deal with things and then he goes, 'Oh God, I sound like Oliver,'" executive producer Andrew Kreisberg said. "These people all do know each other and they're all friends, especially Barry and Oliver. It's probably my favorite part of all three hours is them having a beer together. It's part of the story they always come together because of crises. Those little moments, like in last year's crossover when they were all, before The Vandal Savage attacked and they were all just having a drink together, like they do care about each other. They are brothers in arms."

That's how the crossover ended, of course: once everyone went home or back to their own time/universe, Barry and Oliver went out for a beer and toasted their weird, wonderful, superheroic lives.

"It's those little quiet moments between the fights that are the most interesting to me, as a writer and as a viewer. Hearing those little shout outs along the way, I think is, does a service to the relationships that they've all formed," Kreisberg continued. "It isn't like the crossovers of the 80's where they'd see each other for that one episode and then it was like it never happened. These things do happen and they do have ramifications and not all the ramifications are always bad. Some of them are just good because now these people have these amazing relationships that continue on."

Arrow, The Flash, and Supergirl will cross over with DC's Legends of Tomorrow this week in "Invasion!" a three-part crossover that starts in the final moments of an episode of Supergirl and then plays through the other series. Based on the 1988 comic book event miniseries Invasion! from Keith Giffen, Bill Mantlo, Todd McFarlane, Bart Sears, and the crossover -- with its marketing title "Heroes vs. Aliens" -- will closely track the plot of that storyline: aliens will be assembled by The Dominators and descend on Earth to bring an end to the "threat" of Earth's burgeoning metahuman community.

In the comics, the Dominion were secretly hoping to build their own super-race, and as a result created a handful of new superheroes in the course of the story.

NEXT: The Flash, Arrow, Supergirl, Legends of Tomorrow Crossover Trailer / First Look At The Dominators / Invasion! Crossover Promo Photos / Potential The Flash Spoiler Spotted On Set / Will Joe West Die During The Invasion! Crossover? / Enter To Win An Ultra-Rare Invasion! Crossover T-Shirt

Supergirl airs Mondays at 8 p.m. ET/PT; The Flash on Tuesdays at the same time; Arrowon Wednesdays and DC's Legends of Tomorrow on Thursdays. All four series air on The CW. The "Invasion!" crossover will air beginning November 28.