'The Flash' Season 4 Spoilers: What Kind of Villain Is The Thinker?

"The Flash" season 4 is coming back soon, with a premiere air date slated for October 10, Tuesday. Fans can expect a new villain who is the smartest they've ever faced, as well as the return of everyone's favorite Scarlet Speedster. But does Barry Allen come back a changed man? Spoilers follow.

In "The Flash" season 3 finale, Barry Allen left his friends and his fiancee to go into the Speed Force. This was the only way to restore the destabilized Speed Force threatening to destroy Central City. It was also Barry's penance for his reckless act of changing the timeline, which had caused the whole mess in the first place.

The CW's preview trailer (seen below) showed that Barry would be back, as expected. On his return, he will be facing the show's first main antagonist who is not a speedster: Clifford Devoe, The Thinker, played by "The 100" actor Neil Sandilands.

Todd Helbing revealed to TV Line that season 4 villain The Thinker will be someone fueled by a psychological concern stemming from a personal experience that drives him to go bad. And as he is the most intelligent man in the world, The Thinker will constantly be misdirecting Team Flash as to the true nature of his plans. Helbing even suggests that the audience may get to know the bad guy's schemes before the heroes do, putting them a few steps ahead of the gang.

Previous information released about the character suggested that The Thinker will be driven by the desire to fix what's wrong with humanity. It's not yet clear how that aligns with Helbing's hints, but it sounds as though this version of The Thinker will have some similarities to the villain of "Watchmen," which coincidentally is currently under development in HBO.

The team will need all the help they can get dealing with, so in season 4 they'll have assistance from a super-powered detective. Classic DC hero Elongated Man will be appearing in "The Flash" this season. Also known as Ralph Dibny, Elongated Man is a metahuman who can stretch his body parts to fantastic lengths. Deadline says he will be played by Hartley Sawyer.

There are several more exciting guest appearances expected in season 4. One is the villainous Amunet Black, a.k.a. the Blacksmith, who has the power to manipulate metal. "Battlestar Galactica" actress Katee Sackhoff has been cast in the role. Den of Geek reports that "Machete" star Danny Trejo will appear as Breacher, a bounty hunter who happens to be Gypsy's father.