When SH is on his way to get Grendael she thinks she might be able to flee to a mirror world where the DO has less of a grip then he does in Randland. This indicates to me that at least one chosen knows how to use the portal stones, why not Demandred or Moridin?

I believe the red veiled and dark eyed Aiel with their teeth filed to points as seen in the epilogue are actually a clan brought from the portal stones from some evil Aiel in a mirror world. The one we saw did not kill with the One Power. He killed with a spear. Demandred's rule is secure according to the TGS Prologue. Why can't he rule in a mirror world where the DO has a better grip on the population. In this way he could stay out of the way until the last second and spring this huge surprise on the Light for the LB.

This would indicate why Demandred has been largely absent as well. He didn't grab a power base anywhere where he could be found easily. I think he might also have a school of Channelers in the Blight as well which DomA has so eloquently indicated numerous times on this board in reference to Demandred's whereabouts. If I was him I would also have secured my own Aiel to help deal with the Dragon Reborn's stongest military force. It would be quite brilliant of him to have used mirror worlds in this way as well. Not a dissapointment like if he turns up in Murandy as King there, which would really suck in my opinion.