With San Diego Comic-Con going on right now, we’ve seen some rather awesome new trailers for the return of The CW’s DC-based shows. And in amongst all of that, there’s also plenty of new casting news for Arrow, The Flash, DC’s Legends of Tomorrow, and Supergirl.

In the biggest piece of casting news for this shared small screen world, The Flash has found the ‘big bad’ of its upcoming fourth season. While we’ve previously known that the genius, telekinetic, mind-controlling Thinker will be the main villain of Season 4, it’s now been revealed that The 100’s Neil Sandilands will the playing Clifford Devoe, aka The Thinker. On board to play his sidekick, a mysterious figure dubbed The Mechanic, is Dominion’s Kim Engelbrecht, and another new confirmed cast member is Machete’s Danny Trejo, who will be playing Breacher, the Earth-19 bounty hunter father of Gypsy. Season 4 of The Flash is set for an Octoberth 10th premiere.

Where the show that started this whole world is concerned, Arrow has added Lost’s Michael Emerson to its ranks for the Stephen Amell-headlined series’ sixth season. At this stage, there’s no word on just who Emerson will be playing, although the mystery role is confirmed to be a recurring presence throughout the upcoming new season. And in additional Arrow news, David Nykl is confirmed to be reprising his Anatoly Knyazev role for Season 6, which premieres on October 12th.

With the recent trailer for Supergirl suggesting that Melissa Benoist’s titular Maid of Might is looking to leave the Kara Danvers persona behind, the series has moved to bring in several new faces ahead of its third season. As the ‘big bad’ of the season, House and Cloverfield’s Odette Annable has been cast as the nefarious Reign, one of DC’s infamous Worldkillers. On a less superpowered level, Heroes and Agents of S.H.I.E.L.D.’s Adrian Pasdar has been brought in as Morgan Edge, a ruthless property developer who will soon be at odds with both Supergirl and Lena Luthor. And then there’s Alias’ Carl Lumbly, whose signed on to play a DC comic book classic of olde, M’yrnn J’onzz – the father of David Harewood’s J’onn J’onnz, aka Martian Manhunter. In Supergirl, M’yrnn will be depicted as a pacifist and religious leader from Mars who ends up pushing his son in ways yet seen in the show. Of course, longtime DC fans will be well aware that this isn’t Lumbly’s first ties to the Martian Manhunter, with him having voiced the character in the animated Justice League series. But that’s not it for new additions, for Supergirl has also added Jane the Virgin’s Yael Grobglas as psychic villain Psi, and Elysium’s Emma Tremblay as street-smart National City kid Ruby. Supergirl returns to US screens on October 9th.

Switching our attention to the time-travelling shenanigans of DC’s Legends of Tomorrow, and no new cast members have been confirmed for the series just yet. There is, however, some news on some returning faces. Both Wentworth Miller and Arthur Darvill have been confirmed to be returning as Captain Cold and Rip Hunter, respectively, in guest star spots for Season 3, while Neal McDonough will be back as a series regular as he reprises his role as the villainous Damien Darhk. Said third season of DC’s Legends of Tomorrow is currently set for an October 10th premiere.

In terms of UK premieres for these new seasons, nothing has been officially announced as of yet, although we’d say to expect the UK airings to follow shortly after the shows make their US returns.