The plot of Cymbeline features several characters who are noble by birth but behave ignobly, while other characters do not know of their noble origins or must disguise them, yet behave with honor and courage. Throughout the play, Shakespeare thus interrogates the influence of nature versus nurture on character. 

Cymbeline’s children are inherently noble, suggesting the role of nature in influencing their character. Imogen’s virtue is such a fundamental part of her character that it is even apparent when she is incognito. She also withstands external pressures to marry Cloten or to sleep with Iachimo. Arviragus and Guiderius’s nobility is likewise so innate that their upbringing in a cave does not change it: Imogen notes that they are as noble as any courtier would be in the same circumstances, suggesting that they do not behave exactly like courtiers, but that these differences are superficial compared to the primacy of their inherent qualities.

By contrast, the Queen and Cloten are portrayed as fundamentally wicked, with no redeeming qualities despite their noble blood. The Queen’s confessions in Act V place her in the role of a ruthless Machiavellian villain: Even her personal relationships were actually motivated by ambition and greed.