Christianity's Satan is a creature, not a rival power, and this is doctrinally load-bearing: the tradition rejected dualism early and hard, because a genuinely equal opposing force would make the outcome uncertain. Much of the popular picture — the fall from heaven, the horns, the underworld throne — comes from Milton, Dante, and folk imagination rather than scripture, and modern theologians differ on whether the figure is personal or a way of naming structural evil. The name means accuser, and the earliest biblical appearances are of a prosecutor in a heavenly court rather than a rebel.