How was evil portrayed in Elizabethan era theatre?
Evil was portrayed either as a vice (embodiment of the devil) or in the Machiavellian form using imagery of either nature (predadorty animals, sick plants etc) or any other unpleasant imagery (sores, decay etc.). Read Shakespeare’s Richard the Third, King Lear, Macbeth etc. If you are really interested in further study of this The Prince by Machiavelli is also a good source.