Assassin of the Empire

In my campaign, the Assassin in the Guild operate more as spies than killers. They are the secret police for the Emperor, persevering the peace through whispers and intimidation. Since the Human Empire is at war with dwarves and elves, assassins have a noticeable inability to infiltrate these societies. Sleep and height basically preclude it. Silly, but reasonable. They aren't sidelined by this lack, instead they keep the roads clear for the troops and citizens alike. They handle messages at all levels of government and even provide a private mail service. 

In this campaign assassins tend to work like urban and rural rangers, where the road between counts as a part of the creating town or village. Why not simply make them rangers? Because rangers operate completely without support in the wilderness, where as assassins and spies use and misuse resources already in place. Assassins require civilization to abuse, while rangers don't care about what everyone else is doing. Some of their skills collide, such as being knowledgeable about the lay of the land, habitation, trails, roads and alternate routes. But assassins can only work when they have the civil pact to violate. An assassin the woods is just as lost as a ranger in a church or temple.

Assassins will know the roads, the towns and the important places within the town. They are often attached to patrols to act as guides and reporters to civil agencies. They know the important people, and not just the people that think they are important. Assassins know the right scullery maids and court clerks. Rangers know different facts, which are clearly not in the same circle.