Lady Sybil Crawley

The youngest and most spirited of the Crawley daughters, Sybil is restless inside the house's rigid rules from the start. She's drawn to politics and progress, sympathetic to the servants as people rather than staff, and impatient with the idea that a well-bred girl's future should end at a good marriage.

Downton gives its aristocrats plenty of wit but Sybil gets conviction, and Jessica Brown Findlay plays it without a trace of preachiness — her curiosity feels like genuine appetite for the world rather than a scriptwriter's soapbox. She makes idealism look like the most natural thing in the world for a girl her age to have.