False protagonist

In fiction, a false protagonist is a literary technique, often used to make the plot more jarring or more memorable by fooling the audience's preconceptions, that constructs a character who the audience assumes is the protagonist but is later revealed not to be.

A false protagonist is presented at the start of the fictional work as the main character, but then is eradicated, often by killing them (usually for shock value or as a plot twist) or changed in terms of their role in the story (i.e. making them a lesser character, a character who leaves the story, or revealing them to actually be the antagonist).