Outside The Sandman Mythos
In Jewish folklore, Duma is the angel of silence and death's stillness; the Hebrew word "Dumah" means silence. According to the same stories, he is the guardian of Egypt and the prince of vindication, and sometimes is called the angel who killed the firstborn Egyptians in Moses' time. At least one source names him a "Prince of Hell"; meaning that at some unknown point in time, he apparently displeased God and fell from grace.
The Zohar, a book of Jewish mysticism, describes his position in Hell as such that he had "tens of thousands of angels of destruction" under him, and that he was "chief of demons in Gehinnon (Hell; a more familiar spelling is "Gehenna") with 12,000 myriads of attendants, all charged with the punishment of the souls of sinners."
In Babylonian mythology, Dumah is the name given to the guardian of the 14th gate, a gate through which the goddess Ishtar passed on her journey to the underworld. It is unclear whether the Babylonian and Hebrew mythology are related.
Read more about this topic: Duma (DC Comics)