Die, Stygian Jackal!
Contributed by: Joel Sammallahti (firstname.lastname@example.org). This is a set of optional rules to flavor up the D20 combat system for some brutal Hyborian Age action. It is a combination of some popular (and unpopular) house rules used by many gamers. You may experience difficulties when using these rules with nonhuman characters and monsters. They are primarily intended for humans and humanlike creatures. They are intended to balance well with normal D20 combat -- in fact, you could even mix characters using different systems. Many prosperous adventures to you, and may Crom reserve his wrath for your enemies! -- Joel Sammallahti
Note: These optional rules can also be downloaded as a Word document from the Downloads section.
On Hit Points and Armor Class
In standard D20, characters can get an enormous amount of hit points over time, becoming all but invulnerable to normal weapons. Supposedly, this represents the ability of experienced adventurers to reduce injury by rolling with blows and dodging them at the last moment.
However, this means that a successful blow against an experienced character isn't really very successful at all, and does not go well with Howard's fiction. In the Conan stories, adventuring characters -even experienced ones- are not killed by a slow accumulation of nicks and bruises, but by a couple of well-placed, powerful strikes. No human -- not even Conan -- can get hit with a sword ten times and still just keep fighting.
How, then, does Conan avoid getting killed? By not getting hit at all. He dodges, ducks and parries his way through Pictish tribesmen and terrifying monsters.
Notice that Conan rarely wears any substantial armor. Its weight would slow him down and its noise would negate any attempt at stealth. So it isn't armor that makes him harder to hit than the average man. Armor is most useful in actual war, when the ability to dodge a strike is impaired by the confusion of battle and movement-obstructing warriors. In such a situation, it is good to wear a layer of leather or metal on your vital spots to reduce the power of any strikes an opponent might land on you.
In D20, then, we see that the roles of experience and armor in avoiding damage are oddly reversed: experience absorbs damage, armor makes you harder to hit. To simulate Howard's style of sword and sorcery, we must change this.
The new Hit Points
A zero-level character has a number of hit points equal to his Constitution plus his Strength modifier.
If Constitution or Strength changes, even temporarily as in a barbarian's rage or due to poison, hit points change along.
Experienced characters do get extra hit points, but not that many. Each time a character levels up, roll the hit die as usual, adding the Constitution modifier. (At 1st level, don't roll. Just take the highest result possible, as normal.)
The result, however, is not added directly to the character's hit points. It is interpreted as follows:
When a character has lost more than half of his hit points, his wounds start taking their toll and he becomes fatigued. He will remain so until he has healed up to half of his hit points again.
Armor Class becomes Defense Class
Defense Class replaces Armor Class as the target number an attack roll must pass. Defense Class is not affected by armor, but your Dexterity modifier still applies. Your Defense Class equals 10 + base Defense bonus + Dexterity bonus + Shield bonus.
Each class has a Defense progression, like the base attack bonus progression. For standard classes, these can be derived from their hit die. This is reasonable, since hit points are the primary experience-based defensive factor of classes in standard D20, and the Defense bonus occupies that position in these optional rules.
When creating a new class, feel free to separate the hit die from the Defense bonus progression. They need not be related. Remember that the Defense bonus is the more important of the two.
The following is a Defense bonus progression chart based on hit die. It only goes up to level 20. If a character reaches level 21, the progression starts over again, stacking fully.
A multi-class character must determine the bonus for each class separately and then add them up, just like he does with base attack bonuses.
Whenever you lose your Dexterity bonus to Defense, you also lose your base Defense bonus. You can't dodge when tied down! Uncanny Dodge and such abilities and feat affect the base Defense bonus along with the Dexterity bonus.
Armor has no effect on your Defense, as long as you have the appropriate Armor Proficiency. If you lack that feat, the armor penalty is applied to your Defense!
Shields are different from armor in this respect, however. They do, in fact, make it easier to evade blows by deflecting them, and therefore add to Defense. They do not behave as armor, reducing damage dealt.
It is easier to defend against one attack than it is to defend against many. To simulate this, we use the Concentrated Defense bonus.
This Concentrated Defense bonus can be used once each round to defend against a specific attack. It adds to your Defense Class against that attack only.
You must declare that you are using your Concentrated Defense after the attack is announced but before the attack roll is made.
The magnitude of Concentrated Defense depends on your base Defense bonus.
Concentrated Defense has no effect on your attacks. It can be combined with Total Defense (no attacks, +4 to Defense).
Armor absorbs damage
Armor is made for one purpose: to take the damage from a weapon strike instead of your body. It literally gets in the way of incoming strikes, but if those strikes are strong enough to penetrate through the armor or send destructive shock waves to your flesh, then you still get hurt -- but not as much as you would have without the armor.
Armor therefore works like damage reduction. However, it isn't evenly spread around your body. You always armor certain vital spots more than others, and there are always openings and weak spots. For this reason, and because roleplayers love to roll dice, the damage reduction against each individual hit is randomized.
A suit of armor has an absorption statistic, which replaces its AC bonus. Determine the absorption of existing suits of armor from their AC scores by this short table: