Bruno Heller the showrunner for the Gotham TV series has revealed that noted Batman villains Harvey Dent (aka Two-Face) and Professor Hugo Strange will both appear as first season characters on the Gotham TV series, which focuses on young policeman Jim Gordon and depicts the mean, pre-Batman streets of Gotham City.  Of course since the entire Gotham series is a "prequel" of sorts, villains like Poison Ivy, Riddler, The Penguin, and presumably The Joker will be seen early in their careers. 
 
There will also be changes from the comic book continuity.  Heller told IGN, "We're playing Harvey Dent slightly older. He's more Gordon's age in this telling."  It is likely that the Harvey Dent in Gotham will be more of the idealistic lawyer/DA and not the tortured villain of the Batman sagas.  In fact the other villains announced for the show like Oswald Cobblepot (The Penguin) are likely to be considerably less flamboyant in their youthful Gotham incarnations.  Heller was careful to admit that the writers of Gotham were trying to show restraint and not try to include too many characters from the overstuffed rogue’s gallery of Bat-villains.
 
But some of these dark side characters appear to be absolutely essential for the new Gotham series, and Hugo Strange is one of them.  Heller explained: "Hugo Strange is going to pop up because we're going to start dealing with how Arkham was created and why Arkham was created in the way that it was so, yeah, absolutely.  It's a Season One thing because in our telling of it the way Arkham was created and the why and how it is one of the causes of the particular criminal climate in Gotham that allowed Batman to happen.  The revolving door of Arkham is both a brilliant narrative device because it allows you to--you don't have to kill people off, you can just put them in cold storage -- but if you're telling the story from the start you kind of have to explain, 'What the h***?  Why don't you make that place a place people don't escape from?'  We're going to explain why it is the way it is and Hugo Strange is a big part of that."
 
Gotham is set to premiere on Monday September 22nd on the Fox Network.  To get a flavor of the new series check out the first trailer here and the most recent spot here.