Where is Demandred?
Part of the fun in Robert Jordan's Wheel of Time series is observing where each of the Forsaken choose to hide themselves; how each of their personalities leads them to advance the cause of the Dark One in distinctly different ways. At the end of Winter's Heart, the whereabouts of almost all of the Forsaken is known: Aginor and Balthamel died but were resurrected (Aginor summarily died again), Be'lal and Rahvin have been slain by balefire, Sammael is dead, Asmodean was killed by agents of the Dark One, Lanfear died to be resurrected as Cyndane, Moghedien is captured, Ishamael became Moradin, Mesaana is in the White Tower, and Graendal is in Arad Doman. Two Forsaken, however, have not been clearly identified. Semirhage has not been mentioned enough to locate, but events will let us give a very good guess as to where Demandred is. Demandred is Mazrim Taim.
First off, Taim is clearly a bad guy, after ordering the attacks on Rand. Also, the voice of Lews Therin and its violent feelings towards Taim indicate that Mazrim is no ordinary Darkfriend. The title of M'Hael, meaning "leader", could very well reflect Demandred's need to be acknowledged as great.
I am not saying Demandred claimed to be a false dragon. It is my belief that after the Aes Sedai captured the real Taim, agents of the Dark One "rescued" him, killed him, and introduced Demandred to Rand as Mazrim Taim. This would explain Sammael's cryptic remark: "Events to the south had Demandred's mark all over them; the man always did like using proxys." The proxy referred to, in this case, was the real Mazrim Taim.
Incidentally, that quote by Sammael implies that enough information has been given for the reader to puzzle out where Demandred is for himself. If any of you have conflicting ideas, let me know.