is that Graendal knows nothing about Demandred's whereabout despite having spies everywhere and being noted (several times) as not neglecting Shara. We do not hear of a new ruler there but of a civil war that. And that civil war was not caused by unknown Demandred machinations but by Graendal's involvement in the land.

In any case the Sh'botay is only ruler of Shara in name. And there was no indication that a new pair of puppets were chosen anyway. The true rulers are the female channelers of that land. They keep male channelers like Demandred in the breeding kennels.

Demandred might as well spend his days as the secret forsaken hiding in plain sight in the house of the secret forsaken Graendal. He'd have a better chance to influence the world from there.