Who were the sleepless watchers of Minas Morgul and their fate?

[BalrogRingDestroyer]

It's been a while since I read the Two Towers, but recall that there were these sleepless watchers inside the place that weren't Nazgul but couldn't be Men either. What were they? And were they kept up by the Ring's power, thus being destroyed when it was ruined, did they die when the Tower was destroyed by Gondor, or did they just leave and disappear, like the Mouth of Sauron?

 

[zooeyhall]

I would say that they were sentient statues. And although inanimate, housed spirits of evil placed there by Sauron.

As to what happened to them--I suspect it is the same as what happened to all of Sauron's works after the destruction of the One Ring. They were also probably destroyed.

 

[Olorgando]

It's been a while since I read the Two Towers, but recall that there were these sleepless watchers inside the place that weren't Nazgul but couldn't be Men either. What were they? And were they kept up by the Ring's power, thus being destroyed when it was ruined, did they die when the Tower was destroyed by Gondor, or did they just leave and disappear, like the Mouth of Sauron?

I would say that they were sentient statues. And although inanimate, housed spirits of evil placed there by Sauron.
As to what happened to them--I suspect it is the same as what happened to all of Sauron's works after the destruction of the One Ring. They were also probably destroyed.

There were sentient statues at the lower entrance to the Tower of Cirith Ungol, which Sam managed to overcome by the use of the Phial of Galadriel - and his own determination. When he managed to overcome them the second time on the way out, they crumbled. Anything similar at Minas Morgul, or at the Black Gate, would probably have been seriously more powerful; but nothing could have matched Barad-dûr, which was destroyed including its foundations at the destruction of the One Ring, while the foundations had proven indestructible at the end of the Second Age. So anything depending on Sauron's evil power is likely to have crumbled when the greater part of that power was destroyed with the One Ring.

 

[d4rk3lf]

I always imagined they are sort of similar evil ghost as the Barrow Wights, only trapped in statue.
Since that's an entrance to Cirith Ungol, I wouldn't be surprised if Witch King himself placed them there, since it was his tower, and he also created Barrow Wights.
Maybe Sauron didn't even know of their existence, or they were very insignificant to him, to pay any attention to them (just a toys of Witch King)