Active Defense

In this campaign, we will use an adaptation of an Alternate Rule used in Pathfinder’s Ultimate Combat. The goal is to give the player a hand in defending himself when his character is attacked in combat. As such, characters in this game will not have AC. They will instead have a Defense Bonus, and a Damage Reduction. It is very easy to calculate these scores.

Defense Bonus
Your Defense Bonus represents your character’s skill at defending himself in combat by means of dodging, parrying, and blocking attacks. To get this score, follow the formula below.
DB = Base Attack Bonus + Max Dex Modifier in current armor + Shield Bonus + Magic Armor Enhancement + Dodge Bonus +/- Size bonus + Any other bonus related to avoiding being hit

CMD
Calculating your CMD is even easier. Simply use the normal method of calculating CMD, but do not add the base 10 that is normally added. So…
CMD = Base Attack Bonus + Str Modifier + Dex Modifier + size modifer + misc. modifiers (feats, gear, etc)

Damage Reduction
If your Defense Bonus represents your ability to get out of the way, your Damage Reduction represents your armor’s ability to absorb some of the blow when you do get hit. It too is easy to calculate.
DR/armor = Armor Bonus + Magic Armor enhancement + Natural Armor +1 per 5 hit dice

Other Rules and Notes

Losing Dex Bonus
Just like the normal system, you can be caught flat-footed and lose your Dex bonus. When this happens, you lose your DEX and Shield bonuses to your Defense Bonus.

Touch Defense
Your touch defense includes all aspects of your Defense Bonus except for shield and magic armor enhancement.

Armor Proficiency
Wearing Armor or using shields that you lack the proficiency for causes you to take the Check Penalty of those armors to your defense bonus.

DR from other sources
Unlike most forms of damage reduction, DR/armor stacks with other types of DR. For instances, when fighting a skeleton with DR 5/bludgeoning and DR 4/armor (+2 for armor, +2 for natural armor ), the skeleton’s DR/armor reduces 9 points of damage from non-bludgeoning attacks, and 4 damage from bludgeoning weapon attacks. DR/Armor is not automatically bypassed by magic weapons.

Critical Hits and Active Defense
Scoring a critical hit works the same in this system as in the normal. When you threaten a crit, roll another opposed check to confirm and proceed as normal.

Critical Defense
As with offense, so with defense. If you roll a natural 20 on your defense roll, the attacker automatically misses regardless of his roll. If both the attacker and the defender roll criticals, resolve the attack normally. Characters with good Base Attack Bonuses can gain access to Defense Feats that improve their defensive Crits. (see New Feats)

Active Defense

Mark of Vengeance Summerhawk