The Flash season four will pit Barry Allen against Cliff DeVoe, a.k.a. The Thinker, according to TVLine. TVLine reports that an unnamed source confirmed to them that Thinker would be the "big bad" of season four, following several teases about the introduction of the character in The Flash's third season.
In comic books, the Thinker is a technologically-enhanced human with the power of telekinesis and mind control. Though primarily a villain, he was once a member of the Suicide Squad, and prior to Flashpoint, was an employee of the JSA and a member of Checkmate. He has been teased as a future villain in The Flash by his surname, "DeVoe."
The Flash season 4 will premiere on the CW this fall.