Mournguls are Malignants of the Nighthaunt armies. These soulsearing horrors are created from those driven to famine and pain by the cold of a mountain's winter, so starved they are they hunt down companions and friends for meat and warmth of their blood. But these actions do not save them and they instead become thrice-damned condemned eternal starvation and isolation. It is spite, malice and desperation that calls the most insidious winds of magic to their bodies which then twists them to their shape into their inhuman proportions, neither dead or alive, nor revenant nor ghost. They become truly horrific creatures, razor-thin shadows of cold flesh and cracked bone with a gaping maw full of needle-like teeth. Their cavernous stomach hangs open like a dreadful wound.
These ethereal creatures, difficult to harm with ordinary weapons, can fly and usually attack with their nightmarish claws and fangs, which not only twists and warps their form its touch can still the heart of a mortal opponent. Mourngul can devour not only the flesh, but also the souls of those it kills, healing themselves in the process. Even their appearance is a weapon, so horrifying it is to look at it that it radiates an aura of supernatural terror, unutterable despair and ravenous hunger.