According to a recent report from Hollywood Chicago – Chicago being the current location for TDK filming – it looks as if Hall will not be playing the Riddler, or his predecessor Edward Nygma, as many had hypothesized.
Apparently it looks as if Mr. Hall will be playing an investigative reporter who not only finds himself thoroughly disliking Mr. Wayne, but also discovering the true identity of the masked vigilante. The Joker – the true villain of the movie – finds out about Hall’s characters attempts to reveal the news, and sends in a bomb threat to the station.
All of this is still only rumor and speculation, but Hollywood Chicago has shown itself to be a reputable source for getting information right on the money, so it could be that the third movie will just be a Harvey Dent/Two Face spectacular, rather than a dual villain movie.