The characters in a play. Rarely used, as Webster 1913 has it, to refer to the actors. The latter usage is arguably wrong, as the Latin word persona suggests "character" or "role" rather than the modern sense of "person."
Pedants' note: The expression dramatis personae is plural. It is the Latin for the characters of the play. As a plural, it takes a plural verb form.
Incorrect: The dramatis personae of A Midsummer Night's Dream includes several fae.
Correct: The dramatis personae of A Midsummer Night's Dream include several fae.