Who is Satan from On a Pale Horse and what is their importance?

Satan is constantly present in the novel, and he is categorically evil. Hell runs incessant ads in newspapers, in magazines, on billboards, and on TV to encourage people to turn to Satan and turn their souls over to Hell. He appeals to lust and greed in everyone. By advertising Hell in this way, Satan is cheating on his pact with God not to interfere with human beings. Satan also schedules Luna for early demise to further his control over mortal Earth and bring more souls into Hell.