The third season of Titans will add Mad Men star Vincent Kartheiser in the role of Jonathan Crane, the villain known as the Scarecrow. Once a fairly obscure Batman villain, his appearance in Batman Begins made him a household name, and he has since appeared in Gotham and had a prominent role in the animated Harley Quinn series. It has long been known that Titans was expected to bring Crane into the show, although the big difference is that he will be serving as an adviser to the GCPD, and theoretically not as a villain (unless there's a heel turn planned, which is entirely possible).
The character, who uses a fear toxin to disarm his opponents, was played by Cillian Murphy in Christopher Nolan's Dark Knight trilogy, and then by Charlie Tahan (in the first season as well as the first half of the fourth season), and by David W. Thompson (in the second half of the fourth season as well as the fifth season) of Gotham.
You can see the tweet announcing his casting below.
There's no word as to how many episodes he will be appearing in, or how substantial his role will be. Casting has yet to be announced at this time.
Here's the character's official description, according to WBTV: "Known to most as the Scarecrow, Crane is a current inmate at Arkham Asylum and offers his services as a profiler and consultant for the Gotham City Police Department."
So this take on Scarecrow will already be an inmate at Arkham when he makes his debut, but will still have some pull over the G.C.P.D.
In addition to Scarecrow, Titans will be adding a couple of other Gotham-centric characters to its third season. Curran Walters will finally take on the role of Red Hood, while the Barbara Gordon will be making her Titans debut.
Season three takes Titans to HBO Max, following the dissolution of the DC Universe streaming service where the show made its debut. The series centers on Dick Grayson (Brenton Thwaites) and the team of young heroes he assembles to take on threats separate from Batman, with whom he has a contentious relationship. You can find the first two seasons on HBO Max now.