'Arrow' Season 4 SPOILERS: How Will Barry Allen's Time Travel Affect Arrow, The Flash?

The annual crossover between Arrow and The Flash has ended, but the fallout from it will continue for the majority of the respective seasons of these two shows. Specifically, how will Barry Allen's (Grant Gustin) time travel affect everyone?

On both shows, we have learned that messing with the natural order, as it were, has consequences. When Barry traveled back in time and relived a day in Season 1 of The Flash, he prevented one disaster while causing other problems. Thea Queen (Willa Holland) is still dealing with the consequences of her revival via the Lazarus Pit on Arrow.

During this year's crossover, Barry again went back in time by one day, which allowed Team Flash and Team Arrow to have a second chance at defeating Vandal Savage (Casper Crump). So what consequences will this have for both series? Executive producer Andrew Kreisberg spoke to TVLine and previewed the trouble ahead.

"When Sara was brought back, when Thea was brought back, last year when Barry changed the timeline, this year when Barry changes the timeline, any of these things that feel like the right thing to do, there is always, always a price to be paid," he said.

Despite all the comic book elements on these two series (time travel, resurrection, magic), it's clear the showrunners want to make sure there are still stakes to what happens on screen. So that means no more death cheats in the future.

"We've certainly taken care of the Lazarus Pit at the end of Episode 3 of [Arrow] Season 4," executive producer Marc Guggenheim told TVLine. He also explained that the spinoff DC's Legends of Tomorrow, which heavily involves time travel, will explain "why time travel can't be used in a deus ex machina kind of way, not just with respect to death, but with respect to any plot contrivance."

What consequences do you foresee for Arrow and The Flash now that Barry has changed the timeline? Let us know in the comments section below.