D&D 5E Reactions

[Ovinomancer]

Being unconscious/dead through damage reducing your hit points to zero would also remove your ability to take reactions...but we know it doesn't! Therefore your assertion cannot be true in the game.

It's like you didn't read what I said.

Sent from my desire to irritate Mustrum

 

[TheWriterFantastic™]

According to the Basic Rules, attacks are resolves in this way:

Making an Attack
Whether you’re striking with a melee weapon, firing a
weapon at range, or making an attack roll as part of a
spell, an attack has a simple structure.
1. Choose a target. Pick a target within your attack’s
range: a creature, an object, or a location.
2. Determine modifiers. The DM determines whether
the target has cover and whether you have advantage
or disadvantage against the target. In addition, spells,
special abilities, and other effects can apply penalties
or bonuses to your attack roll.
3. Resolve the attack. You make the attack roll. On a hit,
you roll damage, unless the particular attack has rules
that specify otherwise. Some attacks cause special
effects in addition to or instead of damage.

Under step three, it indicates resolution occurs in this order: Attack Roll. On a hit, damage and/or other effects of hit, unless rules state otherwise. Jeremy Crawford's Sage Advice are rulings, not rules, based on his design experience with the game -- as such, it's reasonable to consider his rulings being informed by RAI during the design of the game, but he's just one perspective, and the rules are written in such a way to be interpreted by the adjudication of the standing DM at the given table.
Personally, given that the rules on attacks indicate that on a hit, results are then determined, unless the rules state otherwise, I would rule that Shield, Uncanny Dodge, and similar reaction abilities that trigger specifically on a hit would have their effects occur in between the hit and the result -- especially since those two example state that the reaction is triggered when the target is hit by an attack, not damaged by an attack (Hellish Rebuke, for example, is a reaction that triggers on being damaged, not hit).

 

[Cognomen's Cassowary]

Well, looks like we've got a good, old-fashioned time-travel paradox on our hands.

I haven't read through the entire thread, but here's how I would reason this out: Shield is a really unusual reaction, in that it has the ability to undo its own trigger. Logically, that should be impossible, but I don't think that it's intended to be an unusable Catch-22 spell. Rather, I think that its specific (in the game sense) function is to preempt effects which occur "on a hit" by turning that hit into a miss. That's the first reason that I think shield could be used to prevent a shocking grasp.

I agree with Uller that shocking grasp's wording is not specific; if you look at most any attack spell, you will see the wording, "On a hit, the target takes [dice] [type] damage. . . . " The ellipsis here leads into whatever other effects the attack might have, if any. Those other effects thus would presumably happen concurrently with dealing damage, and I think it's generally understood that damage is dealt only after an attack is determined to succeed. Though shield does reverse the hit, it doesn't reverse the damage and the other effects; it intercedes before they occur. I don't see anything specific in shocking grasp to suggest that its anti-reaction effect happens earlier. Looking at it from the other side, would you allow the wizard to see how much damage the great-axe hit will do before he or she decides to cast shield? Probably not, because the success or failure of the attack is determined before the damage is rolled. "When you are hit" happens before "on a hit." That's the second reason I think shield could be used, and also why I think uncanny dodge could be.

Even if you feel that "when you are hit" and "on a hit" are interchangeable, you are left with the shock effect and the shield happening at the same time, not the shock happening first. To resolve this, I would look at the reaction rules, which make it clear that reactions can "interrupt" [verb 1. stop the continuous progression of] another character's turn. I would therefore say that the reaction effect occurs first, interrupting the attack. That's the third reason.

In sum, I would rule that a reaction triggered "when you are hit" happens before spell effects which resolve "on a hit." Shield and uncanny dodge could thus be used as reactions to shocking grasp, but something triggered by damage, absorb elements for example, could not.

 

[ProphetSword]

Something to keep in mind is the rule on page 252 of the DMG, under Adjucating Reaction Timing:

...sometimes the timing of a reaction be difficult to adjudicate. Use this rule of thumb: 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...

 

[TheWriterFantastic™]

Something to keep in mind is the rule on page 252 of the DMG, under Adjucating Reaction Timing:

...sometimes the timing of a reaction be difficult to adjudicate. Use this rule of thumb: 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...

Agreed, but it can still be taken either way: one person will argue that the since the hit trigger would technically finish before the hit's resulting effects are applied to the target, allowing the reaction to occur before damage and other effects are applied, while another person will argue that the hit "finishes" when the resulting damage and other effects are applied. I, for one, would side with the former person -- especially since abilities like Uncanny Dodge don't trigger off the damage to retroactively reduce the damage, like Shield triggers off a hit to potentially retroactively negate a hit, reaction works RAI, after the trigger, the hit, before the results are applied. IMHO. Otherwise, the language of Uncanny Dodge would specifically state that the reaction halves the damage retroactively, if the reaction were occurring after damage and effects were determined, much like Shield is triggered after the whether or not the attack roll is resolved as a hit. Abilities like Uncanny Dodge are intended to be used before the damage and effects are determined or take place -- not when a damage roll result has already been revealed.

 

[Oofta]

Something to keep in mind is the rule on page 252 of the DMG, under Adjucating Reaction Timing:

...sometimes the timing of a reaction be difficult to adjudicate. Use this rule of thumb: 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...

Thanks for citing the DMG, it definitely gives a clear answer to the Shield question.

However, just because there's a clear answer for that one, does not mean that there's a clear answer for everything. The hide rules are another example where you can expect table variation, and as long as the DM tries to be consistent and fair I don't see a problem with it.

As far as shocking grasp, I would say that Uncanny Dodge doesn't work. Why? There is nothing to indicate that uncanny dodge gives you magical healing, you are simply giving yourself resistance to an attack's damage. You take half damage because you react to reduce damage, you don't take full damage and then recover hit points.

When applying damage and effects from an attack there is no sequence that I can see - you apply damage and effects in the same instant. That means that the damage, the shock, the reaction are all happening at the same time.

In cases of a tie (shock stopping reactions vs reaction to reduce damage) there are no clear cut guidelines*, so it's up to the DM to decide how to break the tie.

I'd say shocking grasp stops uncanny dodge if it ever happens because that's how I would adjudicate the tie in favor of shocking grasp since it make for a more dramatic scene "you go to twist away from the mage's hand but as he touches you your muscles tense up and you cannot react quickly".

In the unlikely event it ever comes up in a real game, ask your DM.

*there are of course, guidelines on how to break a tie for many other aspects of the game.

 

[ProphetSword]

Agreed, but it can still be taken either way: one person will argue that the since the hit trigger would technically finish before the hit's resulting effects are applied to the target, allowing the reaction to occur before damage and other effects are applied, while another person will argue that the hit "finishes" when the resulting damage and other effects are applied. I, for one, would side with the former person -- especially since abilities like Uncanny Dodge don't trigger off the damage to retroactively reduce the damage, like Shield triggers off a hit to potentially retroactively negate a hit, reaction works RAI, after the trigger, the hit, before the results are applied. IMHO. Otherwise, the language of Uncanny Dodge would specifically state that the reaction halves the damage retroactively, if the reaction were occurring after damage and effects were determined, much like Shield is triggered after the whether or not the attack roll is resolved as a hit. Abilities like Uncanny Dodge are intended to be used before the damage and effects are determined or take place -- not when a damage roll result has already been revealed.

Except that the PHB, page 193-194 only has three steps to an attack, and the final step includes both the roll to hit and dealing damage.

MAKING AN ATTACK
Whether you're striking with a melee weapon, firing a weapon at range, or making an attack roll as part of a spell, an attack has a simple structure.

1. Choose a target. Pick a target within your attack's range: a creature, an object, or a location.

2. Determine modifiers. The DM determines whether the target has cover and whether you have advantage or disadvantage against the target. In addition, spells, special abilities. and other effects can apply penalties or bonuses to your attack roll.

3. Resolve the attack. You make the attack roll. On a hit, you roll damage, unless the particular attack has rules that specify otherwise. Some attacks cause special effects in addition to or instead of damage.


It stand to reason that since Uncanny Dodge does not specify that it interrupts in the same way that the Shield spell does, it would only be allowed after the final step, based upon what the DMG specifies about timing...but by that point, the special effect from Shocking Grasp has rendered the target unable to take a reaction, so Uncanny Dodge cannot be used.

 

[Oofta]

It stand to reason that since Uncanny Dodge does not specify that it interrupts in the same way that the Shield spell does, it would only be allowed after the final step, based upon what the DMG specifies about timing...but by that point, the special effect from Shocking Grasp has rendered the target unable to take a reaction, so Uncanny Dodge cannot be used.

I don't disagree with your reasoning, but the only way uncanny dodge can work is:
1) restoring HP after damage after it is dealt, which means it is effectively magically healing you. This leads to other issues such as "what if an attack knocks you to 0 HP".
2) The DM decides there is a sequence. The attack is resolved as a hit, but before damage is dealt the rogue dodges so that the damage dealt by the hit is reduced by half. Since the damage happens after the dodge, so does the effect of no reactions.
3) Damage, dodge and reaction all happen simultaneously. In cases of ties where it's not specified how to decide, the DM makes the call.

I go with #3, but I don't see a clear cut answer in the books. It's not the first time, won't be the last.

 

[Hriston]

This seems very clear to me, especially in light of the quoted language from the DMG, p 252. Shield interrupts the 'hit' that triggers it. Uncanny Dodge does not, end of story.

 

[TheWriterFantastic™]

Except that the PHB, page 193-194 only has three steps to an attack, and the final step includes both the roll to hit and dealing damage.

MAKING AN ATTACK
Whether you're striking with a melee weapon, firing a weapon at range, or making an attack roll as part of a spell, an attack has a simple structure.

1. Choose a target. Pick a target within your attack's range: a creature, an object, or a location.

2. Determine modifiers. The DM determines whether the target has cover and whether you have advantage or disadvantage against the target. In addition, spells, special abilities. and other effects can apply penalties or bonuses to your attack roll.

3. Resolve the attack. You make the attack roll. On a hit, you roll damage, unless the particular attack has rules that specify otherwise. Some attacks cause special effects in addition to or instead of damage.


It stand to reason that since Uncanny Dodge does not specify that it interrupts in the same way that the Shield spell does, it would only be allowed after the final step, based upon what the DMG specifies about timing...but by that point, the special effect from Shocking Grasp has rendered the target unable to take a reaction, so Uncanny Dodge cannot be used.

If you scroll up to my post at the top of the page, #73, you'll see that I've highlighted the same excerpt, but from the Basic Rules document.

Step 3 - Resolve the attack - is broken down as "You make the attack roll. On a hit, you roll damage, unless the particular attack has rules that specify otherwise. Some attacks cause special effects in addition to or instead of damage."

If I were to nitpick, I could say the grammar of the entry determines the order of sequence, with periods indicating stops in the sequence and commas indicating pauses: roll the attack [stop], determine whether it hit [pause], roll damage, if applicable [stop], apply special effects, if applicable [stop]. In that interpretation, there are clear breaks in the sequence that would provide instances for a triggered reaction to occur.

Another way to look at it is with the three reaction spells in 5e that trigger off an attack in some way (excluding Counterspell, as it is triggered by the casting of a spell, prior to attack rolls and damage): Absorb Elements, Hellish Rebuke, and Shield. I'll get to Uncanny Dodge after.

Absorb Elements, from the Elemental Evil Players Companion, is cast as a reaction when triggered by specifically by damage of types indicated in the casting time. The description goes further to indicate the effects of the spell retroactively resisting the damage that triggered the casting of the spell.

Hellish Rebuke, on the other hand, is triggered by damage, and the casting time specifies that the spell is cast in response to the damage.

Shield is cast as a reaction when triggered by a hit. The spell's effect goes on to stipulate that if the AC boost would increase the AC higher than the attack roll that had hit the caster, it retroactively negates the hit.

As shown above, Shield is triggered specifically by a hit, while Absorb Elements and Hellish Rebuke are both triggered by damage -- as such, they can be considered separate events. To go further, Shield, being triggered by the hit event, takes effect a mere millisecond before the damage and effects event is resolved, retroactively negating the hit before the subsequent results occur. Absorb Elements is, on the otherhand, triggered by a damage event, which occurs after the hit event, and retroactively resists the damage that has occurred. Hellish Rebuke is also triggered by a damage event, which occurs after the hit event, and is cast in response to the damage event, as specified by the spell.

Meanwhile, Uncanny Dodge is another reaction triggered by a hit event, much like Shield, in that being triggered by the hit event, takes effect a mere millisecond before the damage and effects is resolved, with the effect halving the damage of the subsequent damage included in the damage and effects event in the sequence.

When the attack potentially triggering the reaction is Shocking Grasp, I would consider them in this way at my table:
A tiefling wizard 1/rogue 5 hit with Shocking Grasp, could react to the hit event trigger with either Shield or Uncanny Dodge, since both trigger off of the hit event, prior to the occurrence of the damage and effects event. However, if said character did not use or could not use an available reaction prior to the damage and effects event subsequently taking place, that character would not be able to use a reaction to activate either Absorb Elements or Hellish Rebuke, as their Casting Time entries specify that their triggers are that the damage event, as included in the damage and effects event has already taken place -- at which point, the results of the Shocking Grasp prevent the target from taking subsequent reactions.

But that's just my table -- another DM might interpret it differently, and that ruling would stand at that DM's table.