Through years of practice, application, trial and error, and special training, members of the Brotherhood of Ashrael learned special techniques to deal death to those who required it. The Justiciars also learned how to do this.
The basic assassination is a simple coup de grace-- a full-round action that would provoke an attack of opportunity if used in open combat. Yet the beauty of the assassination is that it is often used outside of combat, or to open combat.
Assassinations can be performed against any foe who his unaware of your presence, or who doesn't view you as any threat. This means you can assassinate someone from a hiding place, or someone you've sneaked up on. Since this generally means you're assassinating someone not during combat, it's obviously allowed to be used outside of combat.
There are several variations of the assassination, some complex and only usable by more experienced killers. They are listed below.
Hidden Kills: Assassinating a target from hiding is always effective enough against that target, and can be done against anyone who comes within reach of your hiding place. But what about the people around you?
If you assassinate someone from a hiding place and there are others around, make a Stealth check at a -20 penalty. This penalty increases to -25 if you use a larger one-handed weapon, like a sword or axe; it increases to -30 penalty if you use a two-handed weapon. If the check is successful, no one saw you kill the individual, and you may even (if possible) drag the body into your hiding place without anyone noticing. If you fail, you are instantly seen and recognized as the killer.
Leaping Kills: Sometimes, the easiest way to catch an opponent unguarded is to strike from above. If you are located above a target, you may need to perform a leaping kill (at the DM's--i.e., my-- discretion). To perform this kill, you must make a successful Acrobatics check to jump to the target; if the target is directly below you, the DC is 15. If you are successful, you must then make a Combat Maneuver check; if you fail, you land prone adjacent to the target and take appropriate damage for the fall. If your Combat Maneuver check is successful, you perform the assassination; if it fails, you land on the target, knocking them prone unless they are larger than you. Either way, you reduce the falling damage as though you had fallen 20 fewer feet than you actually did.
Contested Kills: Starting at 6th level, members of the Brotherhood and Justiciars are able to assassinate even those who know them, but are not yet ready to attack.
