Jeremy Baldwin (I think) asked on Twitter: “What if players did ALL d20 rolling? Attack and defense vs. static monster attack values?” He also wrote a blog post on the topic. The ICONS superhero RPG uses a system in which players do all the rolling, and it works just fine. It gives players a sense of actively defending against attacks, and puts more of their characters’ fates in their own hands. You’ve got nobody to blame but yourself if you roll low, and all that. It’s very simple to convert standard D&D’s passive defense model to an active defense model of the type Jeremy describes.
I’d like to take this “active defense” idea a step further by showing just how easy it would be to incorporate this into D&D 4e right now, and how it could potentially improve in-combat role-playing.
In standard D&D, each character has four defenses: armor class, fortitude, reflex, and will. Each defense is calculated as 10 + 1/2 level + other modifiers. In the active defense variant, each character has four defense bonuses, calculated as 1/2 level + other modifiers. Attackers “take 11″ on their attacks, so that their attacks are static figures of 11 + relevant bonuses. So, for example, the warforged barbarian/paladin Alard has an AC of 26 in standard D&D; in the active defense variant, he would have an armor defense of +16.
An attack on Alard by an ironskin warrior minotaur (from Monster Manual 3) might go something like this in standard D&D:
DM (me): The minotaur swings his greataxe at you. (The attack is +19 vs. AC. I roll a 10.) Does a 29 hit your AC?
Alard (Steve): Yeah, it does.
DM (me): Okay, the minotaur hits for 22 points of damage.
Using the active defense variant, the same attack might go something like this:
DM: The minotaur swings his greataxe at you, seeking to lop off your head. How do you want to defend against the attack?
Alard: I turn my shoulder into the blow to absorb the damage where my armored hide is toughest. (Steve rolls 1d20 and gets a 10, adding 16 for his armor defense.) How’s a 26 for armor defense?
DM: You turned too far, and the minotaur lands a blow between your shoulder blades, or whatever the warforged equivalent is. (I roll damage …)
In this example, the minotaur needs to roll a 7 or higher in standard D&D to hit Alard’s AC of 26, so it has a 70% chance of hitting Alard. In the active defense scenario, Alard needs to roll a 15 or higher to block the minotaur, giving him a 30% chance to block and the minotaur a 70% chance to hit. (Having attackers “take 11″ instead of “take 10″ keeps the probabilities the same on both sides of the mirror. If attackers “take 10,” the probabilities swing 5% in the players’ favor.)
But this system brings up alternative possibilities as well. Suppose the exchange went like this:
DM: The minotaur swings his greataxe …
Alard: I bring up Bryndlgore to block the incoming axe.
DM: Okay, let’s call that a Fortitude defense roll.
Alard: (Steve rolls 1d20 and gets 18, adding 15 for Alard’s Fortitude defense bonus.) How does a 33 grab you?
DM: There’s a loud clang and a shower of sparks as Bryndlgore stops the incoming axe cold.
In this instance, Steve takes a chance, since a monster’s attacks vs. AC tend to be +2 higher than their attacks against other defenses (exceptions exist, of course).
At some point Steve might recklessly decide to take an even bigger chance:
DM: The minotaur swings his greataxe …
Alard: I duck under the swing.
DM: Okay, give me a Reflex defense roll.
Alard: (Steve rolls 1d20 and gets 3, adding 13 for Alard’s Fortitude defense bonus.) Eh, no, 16.
DM: You duck straight into the blow, which deals you (I roll dice) 23 hp of damage.
Now, what if Steve wanted to say, “I just stand there and take it, willing myself to feel no pain”? Could Alard make a Will defense roll to resist damage? Since hit points are an abstraction that includes morale, determination, and other such qualities (insert obligatory Rocky Balboa analogy and why-warlords-can-heal discussion here), why not? A DM who feels that the PC’s chosen defense is particularly inappropriate against the relevant attack can always give the monster’s attack a +2 or +5 bonus, depending on just how wild the suggestion is. If the player can come up with sufficient storyline to support it, why not allow it? Even a suggestion as strange as using armor defense against a mental attack could be workable if the player suggests something like “my shield reflects bright light into the mind flayer’s sensitive eyes.”
I’ve only been thinking about this idea for a few hours, but so far, it really appeals to me. I think it has the potential to encourage better in-combat role-playing, and to make characters feel more active in the battle. If my players agree, I may even turn this thought experiment into a real experiment the next time we play. If so, I’ll let you know how it goes (and, of course, you’ll hear it on the Icosahedrophilia podcast).