Apollo

Healing is associated with Apollo, both directly and through his son, the demi-god of medicine, Asclepius. But true to his dual nature, the god that protected from the disease could also send it. Apollo's many epithets included “Smintheus,” associated with mice and rats, both as their exterminator, but also as the bringer of the plague. The most famous mythical incident of Apollo sending pestilence to those who invoked his wrath was the story of Agamemnon told in the Book I of the "Iliad."
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The king of Argos and one of the Greek leaders in the ''Iliad,'' Agamemnon, holds the daughter of Chryses, Apollo's priest. Chryses asks Agamemnon for her return, but the haughty king refuses. The old man appeals to the god he's served all his life, and Apollo, angered by such disrespect, shoots the arrows of plague at the Greeks for nine days: “with a face as dark as night, and his silver bow rang death as he shot his arrow in the midst of them.” Only after the girl is freed and suitable offerings made to Apollo, does the pestilence end for the Greeks.