To act in a manner that hides one's true feelings and true nature is referred to as "putting on a mask". There are many situations in which people are unable to reveal their true selves. What is hidden under the mask? Why do we wear them? Seeing a character don a mask stirs our imagination in a number of ways.
Very rarely seen without his mask, Meta Knight (from the Kirby franchise) remains a character full of mystery and intrigue.
Have a peek at the masked individuals below and see if you catch a glimpse of what lies beneath.