Underworld demon causes illness in living

Namtar

He is regularly listed among the bringers of disease, and incantation texts name him as the agent behind particular illnesses, which places him in ritual practice as well as in narrative. In the descent narratives he is the functionary who executes the queen's instructions on the visitor, and later, when the gods intervene, the one sent to fetch and to fetch back.

Gallu

Beyond this central myth, the Gallu recur throughout Mesopotamian demonology as a general class of underworld spirit or agent of death, invoked in incantations and apotropaic rituals meant to ward off illness and misfortune attributed to them.