BS said... - Edit 1
Before modification by Etzel at 20/12/2009 07:50:25 PM
The Demandred identity issue has dragged on for so long that he'd have to be a centrally important supporting character just for the revelation to pay off as worthwhile.
Agelmar Jagad, or Talamanes!
That we haven't seen Demandred's alter-ego on screen before TGS, and he didn't want to tell, if he was seen in TGS.
Either way, Demandred can't be Agelmar or Talmanes, or another important character.