https://en.wikipedia.org/wiki/Nergal
"In demonology:
Because he was a god of fire, the desert, and the Underworld and also a god from ancient paganism, later Christian writers sometimes identified Nergal as a demon and even identified him with Satan. According to Collin de Plancy and Johann Weyer, Nergal was depicted as the chief of Hell's "secret police", and worked as "an honorary spy in the service of Beelzebub"."
"In demonology:
Because he was a god of fire, the desert, and the Underworld and also a god from ancient paganism, later Christian writers sometimes identified Nergal as a demon and even identified him with Satan. According to Collin de Plancy and Johann Weyer, Nergal was depicted as the chief of Hell's "secret police", and worked as "an honorary spy in the service of Beelzebub"."