'The Flash,' 'Arrow' EPs Talk Shocking Crossover Conclusion, Future 'Olicity' Fallout

The Flash still 1 - H 2015
Courtesy of CW

[Warning: This post contains spoilers from Wednesday's episode of Arrow, "Legends of Yesterday."]

And just like that, another The Flash-Arrow crossover event is in the books.

Part two of the second annual crossover event aired as an episode of Arrow, and the hour wrapped the introduction of the Legends of Tomorrow cast to a close until the show premieres in January. Oliver (Stephen Amell) and Barry (Grant Gustin) worked together to use the staff of Horus to vaporize the "immortal" villain Vandal Savage (Casper Crump), saving Hawkman (Falk Hentschel) and Hawkgirl (Ciara Renee) from his wrath. But in the final moments, Malcolm Merlyn (John Barrowman) was seen collecting Vandal's ashes, for no doubt some nefarious resurrection purpose.

Seeing as Vandal Savage is set to be the main villain for spinoff Legends of Tomorrow, it's clear that his story isn't done, no matter how "dead" Oliver and Barry think he is. But don't expect to see that story play out on Arrow or The Flash again anytime soon.

"As of right now, we've almost completely saved that for Legends," executive producer Greg Berlanti told a small group of reporters after a screening of the crossover. "But we're not done with the seasons on those two shows yet so I don't want to say we won't come up with some kind of way to reference it."

And taking out the Hawks for his own personal revenge after Hawkgirl chose Hawkman over Vandal in their first life in ancient Egypt is just a small part of Vandal's ultimate goal.

"For him, a lifetime is an eye blink," said executive producer Marc Guggenheim. "He thinks in thousand-year-terms. He's very much a master of the long con. He does have his own personal agenda vis-a-vis the Hawks, but he's got much bigger plans for the world, which you'll have to watch Legends to find out."

Something else that the showrunners decided to save for Legends of Tomorrow is one of the main characters, time-traveler Rip Hunter (Arthur Darvill). Although every other Legends character had an arc on either The Flash or Arrow, Berlanti said they decided to save Rip's introduction for the pilot episode of the new series. 

But the hour also dropped some major bombs on a fan-favorite Arrow couple when Oliver discovered he had a son in Central City and that his mother had paid off his ex-girlfriend to keep the boy's existence a secret from him. Oliver was able to negotiate a deal with his ex: he can continue to visit and be in his son William's life, as long as he doesn't tell anyone about it, including his girlfriend Felicity (Emily Bett Rickards). Expect that monumental secret to shake up "Olicity" going forward.

"It's definitely going to come to a head in the middle of the season," said executive producer Wendy Mericle. "For the arc of Oliver and Felicity's relationship this season, the fact that he's keeping this from her, and true to what we've done on this show, if there's a secret, it's going to come out and it's going to have some serious consequences.

"We're really excited about how that's going to change things, and it's really going to raise the stakes and throw some wrenches into the works of their relationship," she continued. "So far this season, it's been pretty smooth sailing. True to form, we're going to really mine that and there will be some fallout for both of them."

There will also be fallout for all of Team Arrow thanks to Barry. He traveled back in time after their first attempt to take out Vandal backfired, and everyone died. Barry saved all their lives by turning back the clock and refining their plan, but as he learned last season, there will be consequences for changing the future. 

But, warned Guggenheim, "you're going to have to watch" to find out what those consequences are.

Arrow airs Wednesdays at 8 p.m. on The CW.