Svengali

A Svengali is a person who manipulates or controls someone else, often influencing their actions, decisions, or behavior through persuasive or hypnotic means. The term originates from the fictional character Svengali in George du Maurier's novel "Trilby," where he manipulates the protagonist into becoming a talented singer. In modern usage, it describes someone who exercises almost hypnotic influence over another, typically to serve their own interests, often in a subtle or coercive manner.