How many agents are in EmpireTotal War game

There are only three types of agents in Empire: Total War.
Gentlemen handle research, technology stealing, and also allow you to challenge gentlemen of other nations to duels thus eliminating diplomatic problems that would happen from an assassination.

Rakes perform secretive tasks such as spying, assassination, and sabotage.

Missionaries work to convert the populace of a territory to their country's religion. Deploying missionaries to a region you plan to attack will help ease religious unrest after conquering the territory.