Editing Coup-De-Grace: Arena Design (section)

==Cover==
In the basic rules, there are empty spaces, and there are filled spaces. The former can be moved into freely and do not block LOS, and the latter can't be entered, and do block LOS. The following rules add an additional layer of complication. Be careful with how you use cover rules in scenarios, as having too much cover near starting areas encourages entrenching there rather than dynamic movement.
===Obstacles that only partially block shooting===

For example, a fence that can be seen through but not moved through, a low barricade that can be climbed over but which protects against arrows. 

As a good rule of thumb, these defences inflict a -1 penalty on attack rolls made through them. This can be negated by the attacked being adjacent to them (as if he is stood by a barricade, it doesn't get in his line of fire). Likewise, you might rule that cover that can be ducked behind gives double benefit (-2 penalty to attacks) for those adjacent to it against ranged attacks originating from squares not adjacent to the barricade.
===Obstacles that interfere with vision===

For example, a cloud of mist or low-light conditions.

These could have no effect on melee, but protect against long range attacks. Determine a minimum number of squares distance where these conditions count as cover, and beyond this range give a -1 penalty to attack rolls.