Short answers, pulled from the story.
In religious contexts, demonization refers to the reinterpretation of the deities of polytheistic religions as evil, lying demons by other religions, generally monotheistic or henotheistic ones. Christian missionaries used this approach when converting pagan populations, and Judaism and Islam have similar histories. Rather than denying that other gods existed, these traditions often reframed them as corrupt or dangerous entities.
Lucifer, Beelzebub, and Baphomet were originally names associated with other traditions but were progressively reframed through demonization until their identities became synonymous with the devil or Satan of Abrahamic religions. The process went so far that their original contexts were largely forgotten and the names themselves came to signify evil.
Psalms 96:5 exists in three distinct translations: one rendering the gods of the gentiles as nothing, one as idols, and one as devils. The Greek Septuagint, used by the early Christian Church, chose the "devils" reading, and Jerome followed it in his Latin Vulgate translation. The "devils" wording persisted in Bibles until the end of the 20th century, when modern translations reverted to the original Hebrew text.
King Philip the Fair accused the Knights Templar of worshipping Baphomet, a charge that carried religious weight because Baphomet was associated with Beelzebub and resembled Christian images of Satan. The accusations provided a basis to dismantle the order by framing its members as servants of evil rather than simply political opponents.
No. While monotheistic religions have the most well-documented histories of demonizing other traditions, polytheistic religions have also portrayed rival nations' gods as evil in times of conflict. Within Hinduism, the Buddha is revered as an avatar of Vishnu in some traditions but depicted in texts like the Puranas as an avatar sent to mislead those who reject Vedic knowledge.
In modern colloquial use, demonization refers to propaganda or moral panic directed against any individual or group for the purpose of defamation, character assassination, or dehumanization. The term has moved beyond its theological origins to describe secular rhetorical tactics that attribute malevolent qualities to political opponents or marginalized groups.