• "Legends of Tomorrow" is a spin-off series developed by Greg Berlanti, Andrew Kreisberg, Marc Guggenheim and Phil Klemmer.

"Legends of Tomorrow" is a spin-off series developed by Greg Berlanti, Andrew Kreisberg, Marc Guggenheim and Phil Klemmer. (Photo : Facebook/DC's Legends of Tomorrow)

New "Legends of Tomorrow" details will feature two new trailers, as well as "Arrow" villains Damien Darhk and Ra's Al Ghul added to the show.

"Arrow" season 3 main villain, Ra's Al Ghul (Matt Nable) will be featured in the new CW Network spin-off as Nable confirmed that the Demon's Head will be featured in an episode of the show, International Business Times reported.

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However, it is unclear whether Ra's Al Ghul survived his final confrontation with Oliver Queen (Stephen Amell) during season 3 or whether his appearance in "Legends of Tomorrow" will be a result of time travel.

Several fans have speculated that heroes will likely encounter Ra's Al Ghul in the past given that the theme of "Legends of Tomorrow" is all about time travel. There are also reported that Ra's former ally and season 4 main villain Damien Darhk (Neal McDonough) will also be present within the spin-off.

Ra's mentioned to Oliver in season 3 that he plans to kill Damien Darhk in Starling City before he infects its citizens with the Alpha-Omega virus. Perhaps "Legends of Tomorrow" will reveal more insight on both Ra's and Damien's relationship during their time in the League of Assassins before Damien left the to pursue his goals. The implications of Ra's return could also have an effect on Sara Lance/White Canary (Caity Lotz) given the her history with the ninja organization and the deadly effects on the Lazarus Pit making her more violent and unstable than she is already been, Screenrant reported.

In other news, new trailers for "Legends of Tomorrow" will feature the team of heroes travelling to the 70's period and encountering a new foe.

The first promo "Humanity's Last Hope" will feature Prof. Martin Stein (Victor Garber), Jax Jackson (Franz Drameh) and Sara Lance adopting 70's style outfits, Captain Cold (Wentworth Miller) and Heatwave (Dominic Purcell) robbing a museum and Sara, Captain Cold and Heatwave starting a fight in a biker bar.

The second trailer "One Chance" will showcase all eight heroes chosen by Rip Hunter (Arthur Darvill) to help him save the world from Vandal Savage (Casper Crump). The video highlights many actions scenes and a new unnamed villain, who Savage probably sent after the heroes to stop them from ruining his plans of world domination.

"Legends of Tomorrow" will premiere on Jan. 21, 2016 on the CW Network.