The Maelithii (singular Maelith) are the spirits of dead Druchii that occasionally serve powerful sorcerers as familiars.
According to legend, the Maelithii are the Ghosts of Druchii that offended the Dark Mother and were consigned to haunt the earth until the end of time. They feed on the blood of the living and fear the touch of cold iron. [1b]
The Maelithii have the shape of small, thin-limbed figures with long, skeletal fingers. Their faces resemble those of Druchii, but their eyes are solid black and they possess sharp black fangs.[1a] They cannot be harmed through conventional weapons and where they bit their victim, the skin would become bluish-grey and victim would suffer frostbite as their blood was taken. [1a]
They are often used as guardians by the Cult of Khaine, protecting the inner sanctum of important acolytes as well as the main temple in Har Ganeth.[2a] While these entities only spared those who carried the blessing of Khaine, the presence of Tz'arkan managed to drive them away in fear.[2a]