A Dindae
A hideous, foggy-looking creature capable of disguising itself in shadows and moving with utmost silence, the Qímari (Q."Phantoms") or Dindair (S."Silent shades") were the Phantoms of Morgoth, fallen Spirits of the Shadowfolk. Disturbing to look upon because of their vagueness of form (anyone beholding it constantly had to strain their eyes as they gazed, convinced that there was something in that mist; actually, of course, the Dindae was the mist), these Demons were in addition sadists given to sneaking up on things and half-strangling them,then leaving them to jump at shadows forever after.
It was believed that some Dindair had fled to the east after their Masters fall and hid themselves amongst the Men, some of them eventually becoming local Prophets and lieutenants of Sauron in his eastern provinces, others appearing as mighty humans, manipulating local Kings and Lords and acting as their trusted advisors, eventually making themselves the true ruler by making the weak mannish Chieftains their puppets.