The latest updates and spoilers for "Arrow" Season 6 reveal the new trailer for the upcoming four-show crossover event, "Crisis on Earth X." The video features the DC TV heroes uniting against the evil Earth X army led by Overgirl, Blitzen Flash, and Prometheus X, and their reasons for attacking Earth 1.

"Arrow" cast member, Juliana Harkavy, also discusses Oliver Queen's return as the Green Arrow and how her character, Dinah Drake, will react to him reclaiming the mantle from John Diggle.

Invasion from Earth X

The trailer starts off with Overgirl hovering inside the church as Earth X stormtroopers begin their assault.

The Ray explains to the heroes that the Earth X army is building a doomsday weapon. The Flash, Green Arrow, Supergirl, White Canary, and Alex Danvers are preparing for war as they each lead a team to fight the invaders from different battlefields.

The video also introduced other Earth X characters, such as Citizen Cold and Winslow Schott, as they lead the Freedom Fighters. TV Line posted behind-the-scenes photos of the new crossover and it revealed that DC TV heroes are going to Earth X to save Felicity Smoak and Iris West. They are both being held in that world's S.T.A.R. Labs and it is run by Earth X Harrison Wells.

"Arrow" TV series star Stephen Amell stated during the Salt Lake Comic-Con event that the crossover will be like watching a four-hour movie and promised the fans that the story will not disappoint them.

The "Arrowverse" producers announced that "Crisis on Earth X" will surpass the previous crossover and it will serve as the heroes greatest challenge yet.

Oliver Queen returns as the Green Arrow

"Arrow" cast member Julian Harkavy shared her thoughts about Oliver retaking the mantle of Green Arrow from John Diggle and this action will affect Dinah Drake and the rest of the team.

She told Screenrant that Dinah will not be bothered by the decision as long as it will not affect the team's relationship in a negative way.

"I think that as long as it's best for the team, Dinah is game. So I don't think it bothers her that John is the Arrow," Harkavy said." I think what bothers her is that he's the Arrow while he's compromised.

If Oliver went back to being the Arrow before it made sense, she would be upset with that as well."

Oliver passed the mantle of the Emerald Archer to John Diggle in order to balance his work as Star City's mayor and being a father to William. Unfortunately, Diggle has suffered a tremor in his hand and the condition will affect his performance during missions.