-- A quick look at Armor Class in the Conan RPG --
ARMOR CLASS AND ARMOR: Unlike D&D, your AC in the Conan RPG represents how hard it is to hit your character (in D&D, AC represents how hard it is to hit and damage your character). Armor, in the Conan RPG, can absorb damage inflicted on the character (where as, in D&D, armor makes the character harder to hit). Thus, in the Conan RPG, a character can be hit (attack higher than defender's AC) but not damaged (because Armor prevents character from being hurt). In D&D, if the attack roll is higher than AC, then the character's armor is defeated, and damage is applied to the character.
ARMOR CLASS AND DEXTERITY: Your character's DEX score will effect the chance that your character can be hit in combat. Thus, DEX modifier is applied to AC. If a character has a score of DEX 9 or less, then the attribute penalty lowers the charcter's Base Defense. AC 10 is the Base Defense for most characters, but if, for example, a character has DEX 7 (which means a -2 DEX modifier), then that character's Base Defense is AC 8 as he is not as adept at defending himself as the average person.
BASE DEFENSE: For most characters, their Base Defense is AC 10. Base Defense is lowered for characters with scores in Dexterity of DEX 9 or less. Base Defense is the standard passive defense any conscious, non-hindered character will have. If just standing around, not expecting an attack, when a character is attacked, his Base Defense is used. If a character has DEX 10 or higher, his Base Defense is AC 10. If a character has DEX 9 or lower, then his Base Defense is lowered by an amount equal to his DEX modifier.
Flat-footed - Being "flat-footed" is another use of the character's Base Defense. A character can be alert and expecting an attack but still use only his Base Defense. This happens when a character is slow to act--or caught flat-footed. At the start of combat, on the first round only, every combatant is considered flatfooted until their initiative number is played. After the character's turn in initiative comes up, the character is no longer flat-footed for the rest of the combat (but there are specific circumstances that can arise that can make the character flat-footed later in the combat).
PARRY DEFENSE: When a character is actively defending himself and not otherwise considered flat-footed or hindered, he may choose to focus on parrying blows made against him. If using this defense, the character's Parry AC is his Base Defense plus his STR modifier. A shield will increase the character's Parry Defense. Ranged attacks cannot be parried. A shield cannot be used in the Parry Defense and use in a Shield Bash in the same combat round (so, if the shield is used as a weapon, then it cannot be used to incrase the character's Parry AC that round).
DODGE DEFENSE: When a character is actively defending himself and not otherwise considered flat-footed or hindered, he may choose to focus on dodging blows made against him. If using this defense, the character's Dodge AC is his Base Defense plus his DEX modifier. Ranged attacks can be dodged. A shield will only increase a character's Dodge Defense when the character is attempting to dodge a ranged attack. A shield that is used to Shield Bash can still be used to dodge ranged attacks in the same round.
Switching Between Dodge and Parry: A character can switch between Dodge and Parry defenses at will, using his best defense for every single attack, as long as the player states which defense is being used before the attack is made. It is a Free Action to use either defense type and thus a character defending himself does not count against the character's total actions for the round.
HELPLESS DEFENDERS: Characters who are unconscious or tied up are helpless to attacks against them. Helpless characters cannot Dodge or Parry, and they have an effective DEX 0 score--which means a -5 modifier is applied to their Base Defense. Thus, this means that most helpless characters are considered AC 5. In addition, helpless characters suffer a -4 penalty to AC against melee attacks. This means that melee attacks against helpless characters are made at AC 1 (automatic hits) and ranged attacks against helpless characters are made against AC 5. The Coup de Grace rule (page 198) can also be used against helpless characters.
SUMMARY: There are four basic defense modes in this game. Most of the time, characters will be actively defending themselves using either the Parry or Dodge defense types. When not actively defending themselves (or caught flat-footed at the start of combat), a character wil use his Base Defense (his flat-footed defense posture). If a character is unconscious or constrained so that he cannot defend himself, then he is considered Helpless.