Recently, I wrote about an interception system which allows characters to defend allies by blocking incoming attacks. Interception belongs to a broader category of actions that can be taken out of turn. Each broad class group has it’s own type of reaction. Magic-users may try to disrupt enemy casters with counter-spells and thieves may take opportunistic actions.

Counter-spell. There are many different ways of resolving counter-spells, but the important point here for magic-users is that they don’t need to hold an action to be able to attempt a counter. They get one for free. Whether a counter-spell should require some sort of resource cost (maybe burning a spell?) depends primarily on the magic system. A simple “attack roll” system would work well for trad D&D if you want to decrease the opportunity cost of using a counter-spell (1d20 + half-level + int bonus >= 10 + enemy spell level, for example).

Opportunism. This kind of action may be used for something like an attempt to grab a pouch from the belt of a passing enemy. Perhaps a dexterity check is required for success depending on the action in question. Remember that this is a reaction, not a free action.

Characters may not take more than one reaction per turn, and only primary PCs (not retainers) may use reactions. This rule is to decrease potential complexity and to mitigate any game slow-down caused by extra actions. It is not expected that reactions will be relevant during every combat round.

Clerics, being a species of fighter/mage, could (at character creation time) choose either the intercept or counter-spell reaction type. Intercept would be more appropriate for crusader style clerics, whereas counter-spell might be useful to a witch hunter.

7 thoughts on “Reactions

  1. LS

    In the Pathfinder action economy, this would be termed an “Immediate” action.

    Identical in most ways to a Swift action, but can be performed during another character’s turn. (It would also consume your swift action for that round.)

    (A swift action is essentially a free action, as it does not affect your ability to perform standard or move actions during that turn. However, only one swift action may be performed per turn.

    1. Brendan Post author


      I found minor actions quite distracting and time consuming when I played 4E, and it sounds like swift actions are sort of the same thing. My experience was that players treated minor actions like resources that they needed to maximize the utility of every turn, which led to lots of comparisons of do X and Y, or X and Z, or maybe A and Y (and so forth).

      I like the way this reaction scheme doesn’t seem to impinge on the “what do you do?” aspect of a combat turn as it is specifically in response to some NPC action. Players just need to remain aware of potential triggers so that they can jump in with a reaction when appropriate.

      (It was also pointed out to me on G+ that this might help some players stay engaged in combat when it is not their turn, something that I hadn’t thought of, but that seems true and useful.)

      1. LS

        Having not played 4e, I cannot comment. However, having played a shit ton of D&D 3.5 and Pathfinder, I can say with some certainty that players don’t feel obligated to use swift/immediate actions, largely because these actions are pretty rare.

        For example, there was a magic item in one of the 3.5 supplements which was essentially a small, brittle pieces of clay with magic inscribed on it. When broken or crushed, the spell within it (normally healing) was released. These required only a swift action to use, making them more useful than potions. But they would be correspondingly more expensive and more difficult to acquire.

        Another example is something from my own design work. I’ve been off-and-on working on a Pathfinder class. The core of the class is something like an aura of bad luck. Foes within X distance suffer from A, B, or C type of misfortune as determined by the character. I deemed that switching between these misfortunes would be a swift action, because their effect is minor and I didn’t want the player to feel forced to choose between a “useful” action, and a minor tactical consideration.

        You’re right that your system benefits from being reactionary, though. I just thought it might be of interest that there is readily available terminology for what you’re describing.

      2. Brendan Post author

        Ah, that is different in feel from how 4E uses minor actions. For example, most healing in 4E uses a minor action (because apparently they though healer players would feel left out by not being able to attack also). And there are some common rogue powers, if I recall correctly, which you can use to gain “combat advantage,” which allows them to do sneak attack damage.

      3. Brendan Post author

        Given that “reaction” is also used for another common game construct (the social reaction rolls), I should probably use another term. “Interrupt” would probably be my next choice, though I bet some would dislike the association with Magic: The Gathering.

        Immediate action is not bad though, thinking on it, and as you said it would be recognized by Pathfinder players.

  2. LS

    Actually I think what you may be thinking of is “Instant.” Magic cards which can be played at any time, on anyone’s turn, are Instants.

    I can’t think of a game where an “Interrupt Action” exists, with regards to general action economy terminology. It works well since the player will probably need to interrupt someone describing an action in order to perform one of these.

  3. Ramanan

    Just an FYI, 4th Edition has Imediate Reactions and Free Actions like this as well, independent of Minor Actions. You have powers that are triggered by some action.

    Also to fully nerd out, these would be interrupts because they negate the initial action, no? It’s been a while since I’ve played Magic.


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