Basically,
The Templar is the assassin but they can also hunt the assassin's faction, which is harder than reducing the amount of player.
Assassins goal makes them a faction which only kills the Templars, because they are the big bad faction in the game.
Town Guards are just simply guards, which makes them neutral as they only need to hunt for wrong-doers, but they still works for Templar, since the Templar is their boss.
The citizen is just citizen.
Speaking of which, Machiavelli is the one who wrote "The Prince", which is used by Bismarck to unite German.
Bismark is a Templar?