# In case a trigger for a readied action is someone else's reaction, what is resolved first?

I asked if you can ready an action with someone's reaction as a trigger. The answer is YES.

But I'm still not sure - in such a case (i.e. a trigger for reaction being another reaction) - which reaction is resolved first, the triggered one or the triggering one?

Does the readied action interrupt someone else's reaction that triggered it? Is there a possibility of a chain of such consecutively triggering and consecutively interrupted reactions?

• From PHB:  If the reaction interrupts another creature's turn, that creature can continue its turn right after the reaction. But I see a problem - it's not "another's creature's turn". Does it mean that there's no interruption and the triggering reaction finishes first?
– z33k
Nov 9, 2020 at 21:29
• @ThomasMarkov I expect Counterspell would be the best candidate of an example for a reaction interrupting the triggering action. Nov 9, 2020 at 21:39
• @RevenantBacon sure, but here we have a reaction interrupting (or not) a triggering reaction, not action.
– z33k
Nov 9, 2020 at 21:42
• @RevenantBacon you're right (about counterspelling a counterspell), I rest my case :). Would you care to make a proper answer out of it? I'll accept it right away.
– z33k
Nov 9, 2020 at 21:44
• @z33k My actual point was that you can Counterspell a Counterspell. Nov 9, 2020 at 21:45

## The trigger is resolved first

From the rule on the Ready action:

… take your Reaction right after the trigger finishes

This applies specifically to the Ready action; Reactions that don’t depend on the Ready action (e.g. opportunity attacks, reaction spells) have their own rules.

Some of these, like Counterspell , specifically interrupt the trigger (so, yes, you can Counterspell a Counterspell). Others don’t. And one, Shield, has a weird time-travel effect.

However, for anything hanging off the Ready action, the trigger gets fully resolved first.

• I'll set my foot down and say, Shield has no time-travel shenanigans. Fight me. It's the difference in a kid's shootout game between saying "I shot you" or "I shot at you". If there's room for a reaction with the "When you are hit" trigger, it obviously mean right before the attack disembowels you. Occam's Razor, it blocks the strike at the last moment, instead of time-traveling. Beating the AC does not mean the strike went through. Dealing damage and then finishing the Action means. Nov 10, 2020 at 18:58
• @Mindwin you explain magic how you want. I’ll stick with my explanation of magical time travel. Nov 10, 2020 at 20:49

## The Readied reaction is always after its trigger

The Ready actions defines when the reaction is taken (PHB p. 193; emphasis added):

When the trigger occurs, you can either take your reaction right after the trigger finishes or ignore the trigger.

If your defined trigger is someone else's reaction (or whatever act that reaction includes) you can take your Readied action after that reaction has finished.

Other reactions may actually interrupt, ie. resolve before their trigger, which generally only occurs when the reaction modifies or prevents the trigger, such as counterspell and the Lore Bard's Cutting words (which resolves before the effect resulting from the roll).

## You resolve in order of most recent reaction taken.

The full text on reactions:

Reactions

Certain special abilities, spells, and situations allow you to take a special action called a reaction. A reaction is an instant response to a trigger of some kind, which can occur on your turn or on someone else's. The opportunity attack is the most common type of reaction.

When you take a reaction, you can't take another one until the start of your next turn. If the reaction interrupts another creature's turn, that creature can continue its turn right after the reaction.

So we can see here that reactions are instant responses to a trigger. Lets say that the trigger is Bob casting the spell Fireball. Alice, Bob's opponent, doesn't want to take a fireball to the face, and promptly Counterspells, so as not to be burnt to a crisp. Since Bob does want her burnt to a crisp, he decides to Counterspell Alice's Counterspell. So now we have this scenario:

1. Bob casts Fireball
2. Alice Counterspells
3. Bob Countespells

In order for the spell Counterspell to work as intended, the most recently used reaction must resolve first. If we had more wizards available, then we could theoretically have a chain of Counterspells as long as the [number of available casters] +1 (though as a DM, I personally would restrict it to only 4 or 5 reactions triggering off each other)

Since Readied Actions and Reactions use the same rules, we can safely say that a similar chain of events can be perform. Bob Readies an action to attack when Alice attacks. Alice readies an action to attack when Tim attacks. Tim readies an action to attack when Jane attacks. We get to Jane's turn, and she takes a swing at Bob, triggering Tim's Readied Action, which in turn triggers Alice's Readied Action, which then triggers Bob's Readied Action. Then we resolve in revers order, Bob hits, then Alice hits, then Tim hits, then, finally, Jane hits.

• Counterspell is not a readied action though, it's a reaction in its own right Nov 9, 2020 at 22:01
• @Someone_Evil A readied action is a subtype of reaction and uses the same rules. Nov 9, 2020 at 22:02
• This kind of confusion comes from the misplacement of reactions rules that appear partly in the PH and partly in the DMG. The latter handbook states (page 252): "Follow whatever timing is specified in the reaction's description. For example, the opportunity attack and the shield spell are clear about the fact that they can interrupt their triggers. If a reaction has no timing specified, or the timing is unclear, the reaction occurs after its trigger finishes, as in the Ready action" . Would have been nice to see this tidbit in the PH instead, since nobody uses the DMG. Nov 10, 2020 at 14:06
• @KogarashiKaito: great comment. It both settles the matter and pinpoints the source of confusion. For me RevenantBacon's thinking is perfectly fine. Actually, I too would like one blanket rule (i.e. reactions always interrupt) better than our settling here that says: the rule works this way sometimes, and that way some other times. Alas, RAW rules us all :)
– z33k
Nov 10, 2020 at 14:27