Page of Swords
This card is traditionally entitled The Page, but in some modern decks appears as a Princess. The traditional interpretation is about a messenger, an emissary or liaison between separate camps, charged with faithfully representing one side's communications to the other. Because of this role, we do not think of this person as a servant, but rather as a diplomat, facilitating sensitive negotiations, often under difficult conditions.
This person is acting as the eyes and ears of her patron, and so she is sometimes referred to as The Watchman. Even kings are powerless if this messenger chooses to use her access to sensitive information for her own gain, as is implied by her other name, The Spy.
She could even be working as a double agent, playing both sides against each other to serve her own agenda. Her title is really camouflage in itself, serving as protective coloration so she can move among the people unrecognized, collecting information anonymously. Her vigilance often conceals an ulterior motive. She is a watcher who must herself be watched, because she dreams of someday taking matters into her own hands, preempting the plans of her employers.