One thing to keep in mind about the Isle of Madmen is that for the time being it is still only an inside joke about Australia appearing solely on one world map in the BWB - a world map that as far as we can tell do not exist either in Seanchan or in the Westlands. It's never been mentionned in the main series, we have no idea if anyone in Seanchan or the Westlands knows about it. Perhaps it's so untouched by the Breaking that Demandred know of this continent from the AOL, but we can't be sure, nor of the kind of society that may be there. It's not impossible he recruited there, but I think Seanchan, the Westlands, Shara and among the Seafolk men are even more likely.

Seanchan was an immensely controlled Empire, where it was difficult to recruit all the DF sul'dam and damane (not necessarily DF) without the Empress learning of it, or to test men for the ability. Semirhage's actions changed that as the Empire fell in chaos. Sul'dam can now disappear with a ton of damane and so on. Damane can be turned than freed, sul'dam can be kidnapped and turned and they would all make excellent recruits for further training, with already a good basis in warfare.

My feeling is that Demandred didn't recruit from only one place but many. It seems pretty clear now the Red Veils have nothing to do with him, they go too far back and have to be another of Ishamael's creation.

As for Roedran, it makes so little sense. Roedran could be useful if induced to invade Andor and ravage its south now that Caemlyn is a goner, for instance. That would hold the Andoran armies to take care of that.

Of course, Murandians aren't DF, and whatever they do, if anything, can't be openly for the Shadow...

He could also be useful if instead he joins the other rulers but I can no more imagine Demandred invading Andor as Roedran than I can imagine him infiltrating the rulers as Roedran - Demandred's got a war to lead, he can't be infiltrated. If Demandred has anything to do with Roedran, it will be an agent of his near the King, at best.

I get the feeling Roedran is a complete red herring. It's a joke. That sad and contentious excuse for a country can't even get its act together enough to participate in TG - it's the last nation not connected to either the Rand-Egwene alliance or the Seanchan's! I'm pretty sure Roedran will throw his forces at southern Andor to recuperate what he lost and more, and that will have fairly little to do with the Shadow (he's got a rebel embassy with him, some of whom might be BA, but most of all it seems quite clear they're the ones who drove him to unite his country, hire the Band that the Hall wanted out of the way because Egwene was using it as her excuse to keep moving north and so on). I think those women thought they finally managed to make something out of Murandy, but now the King, who's no wiser than ever, will escape their control and attack Andor...