Medieval: Total War/Agents

Princesses
Daughters of the royal line, a princess is a valuable asset to a leader. They act as information gatherers and are invaluable in forging lasting alliances. Offering a daughters hand in marriage does not only propose an alliance, but also may entitle the faction whom she is marrying into rights to your nation's land should the royal line end.

Emissaries
Emissaries act as the eyes ears and mouth of a nations ruler. They have many uses including:


 * 1) Espionage.  (Passive) The agent will gather whatever info he can on the province he is in, be it your own or an adversary's.
 * 2) Negotiating Treaties. (By dropping the Unit on a rival's Emissary or ruler)  This will propose an alliance or a ceasefire if you are at war.
 * 3) Requesting Marriage. (By dropping onto a foreign princess)  This will attempt to convince the foreign ruler to give his daughter's hand in marriage to an bachelor in the royal family.
 * 4) Offering Bribes. (By dropping on a foreign army who is not led by a prince or ruler)  An agent can assess a rival army and offer a lump sum of gold for them to join your faction.  The price depends on the loyalty of the general, his vices and, size of the army he is commanding and the skill of the agent offering the bribe.  This can be a good way to turn the tide of a losing war or bring it to a quick end.  Bribing a province's only army will gain control of the land without a fight.
 * 5) Striping generals of title (by dropping on your own general holding office) Sometimes those appointed titles will need to be replaced.  Perhaps someone better has been found, perhaps they are doing a lousy job or picked up a detrimental vice.  Either way they won't like it and their loyalty will decrease.

Assassin
Assassins can make a ruler's life incredibly difficult by removing their own agents from play. They have one primary role: murder for hire, but also perform espionage while idle.
 * 1) Espionage.  (Passive) The agent will gather whatever info he can on the province he is in, be it your own or an adversary's.
 * 2) Assassination. (Drop on any general, leader, heir or agent)  This will weigh the skill of the mark vs the skill of the assassin.  Other factors play such as border forts.  Agents are the easiest targets, while princesses, generals, heirs and leaders make progressively much harder targets.

Spies
Spies are less versatile than emissaries, but excel at information gathering. Their uses include:
 * 1) Espionage.  (Passive) The agent will gather whatever info he can on the province he is in, be it your own or an adversary's.  A spy in an opponent's territory will also sew dissent among its people while increasing loyalty in your own.
 * 2) Reveal vices. (By dropping on to a rival's general) This will attempt to reveal secrets about the target that may be exploitable or damaging to his image.
 * 3) Open gate. (By dropping onto a besieged enemy's castle)  The spy will attempt to gain access to the enemies gate house, leaving it open for assault.
 * 4) Frame for treason. (Drop onto your own general) This can be useful for removing troublesome generals who have low loyalty are known cowards or have other negative vices.