Crime fiction
A masked villain, also seen as masked mystery villain, is a stock character in genre fiction, "who hides in order to claim unsuspecting victims". It was frequently used in the adventure stories of pulp magazines and movie serials in the early twentieth century, as well as postmodern horror movies. They can also appear in Crime fiction to add to the atmosphere of suspense and suspicion. It is used to engage the readers or viewers by keeping them guessing just as the characters are, and suspension by drawing on the fear of the unknown. The "Mask" need not be literal (although it often is), referring more to the subterfuge involved.