Opposites.

Contrary in nature, character, or tendency; the converse of a fact. diametrically different; having or expressing a contrary view, argument, etc.

'Ariel is the extreme opposite of Caliban'

Opposites always serve us well in acting. It allows us to ask a most useful question that expands the work – what is the opposite of this?

Aristotle, in his Poetics, defines peripeteia as "a change by which the action veers round to its opposite, subject always to our rule of probability or necessity." ... Aristotle says that peripeteia is the most powerful part of a plot in a tragedy along with discovery.