30

Can one use a hellish rebuke as a reaction after taking damage that would knock one unconscious?

A friend and I fought during one game and I hit him, so he would have lost, but used his reaction to finish me, too. (It was awesome :D)

V2Blast
  • 49,864
  • 10
  • 220
  • 304
wOlF
  • 301
  • 1
  • 3
  • 3

2 Answers2

55

Unfortunately, as awesome as this sounds, by the rules, it doesn't work. Hellish Rebuke is a reaction that you take

in response to being damaged

Not "in response to being hit", or "in response to being attacked". You actually have to take damage to use it.

Whenever a creature takes damage, that damage is subtracted from its hit points.

You haven't taken the damage until you've subtracted it from your hit points. If that puts you on 0 hit points, then

you either die outright or fall unconscious

At which point, you are incapacitated and can't use reactions.

Miniman
  • 144,275
  • 45
  • 644
  • 782
  • 1
    Thank you, too. This was my first instinct, too and I would decide to play it like that if I would have been the DM, but I am grateful for the fun experience of a double ko. ^^ – wOlF Mar 13 '16 at 23:50
  • 18
    @wOlF It's possible your DM knew it would work like this but decided it was awesome enough that it was worth allowing anyway! – Miniman Mar 13 '16 at 23:53
  • "You haven't taken the damage until you've subtracted it from your hit points" The RAW doesn't actually say that though. Actually it seems like that interpretation is completely ruled out. Whenever a creature takes damage, that damage is subtracted from its hit points, but, you haven't taken damage until you subtract the hit points? That sounds like 'we won't give you a job without experience, but you can't get experience without a job'-type thinking. Altering HP and reactions are both consequences to taking damage. – Shane Aug 03 '16 at 21:27
  • 1
    tl;dr: "Whenever a creature takes damage, that damage is subtracted from its hit points, but, you haven't taken the damage until you've subtracted it from your hit points." Say wha-?? ;) :D – Shane Aug 03 '16 at 21:28
  • @Shane Taking damage is subtracting it from your hit points. You can't get a job without, yanno, getting a job. – Miniman Aug 03 '16 at 23:35
  • That's fair. I'm just pointing out for anyone that comes along later that (at least from the passages you've quoted) this answer isn't RAW. The OP didn't use the RAW tag and wasn't asking for RAW, and it appears that at a rate of nearly 2-1 people agree with your interpretation of RAI, so that's legit. Grammatically, that sentence structure doesn't describe an identity relationship. "Whenever you next go to the store, pick up some milk" - "Whenever you stub your toe, it hurts" – Shane Aug 04 '16 at 14:37
  • 4
    @Shane Here's a better argument: as explained in the DMG, a reaction always occurs after its trigger unless stated otherwise. The trigger here is taking damage, so by the time you can take the reaction you'll have suffered all of the consequences of that damage, including potentially being knocked unconscious. By that same token, if you were affected by Hypnotic Pattern and took damage, you'd be able to use Hellish Rebuke because one of the consequences of taking damage is Hypnotic Pattern ending. – Doval Jun 02 '17 at 14:01
  • 1
    By the same logic then (since it uses the similar phrasing of "take damage") you can't use Absorb Elements to reduce damage that takes you to 0 HP. Or actually, without really stretching the argument, Absorb Element's resistance would not apply to the triggering instance of damage, since you're arguing that the spell effect takes place /after/ the triggering damage – Niebla Aug 25 '20 at 03:46
  • 2
    Absorb Elements also state "The spell captures some of the incoming energy, lessening its effect on you and storing it for your next melee attack.", which implies it reduces the damage taken. The Shield spell get's a bit paradox-y as well. The reaction trigger is being hit, but the spell itself adds AC that can prevent you from being hit, which was the trigger in the first place. – Spoki0 - Reinstate Monica Feb 11 '21 at 10:30
20

The rules are (my emphasis):

Hit Points (PHB p.196)

Whenever a creature takes damage, that damage is subtracted from its hit points. The loss of hit points has no effect on a creature’s capabilities until the creature drops to 0 hit points.

Unconsciousness (PHB p.197)

If damage reduces you to 0 hit points and fails to kill you, you fall unconscious.

Hellish Rebuke (PHB p.250)

Casting Time: 1 reaction, which you take in response to being damaged by a creature within 60 feet of you that you can see

Reaction (PHB p.190)

A reaction is an instant response to a trigger of some kind, which can occur on your turn or on someone else’s.

There are two possible sequences here:

  • damage (trigger) -> reaction (Hellish Rebuke) -> subtracted from hit points -> unconscious

  • (damage -> subtracted from hit points -> unconscious [all as a single event]) (trigger) -> can't react because unconscious

For mine, a reaction is an instant response to the trigger, and instant means instant; it interrupts the normal sequence of subtracting damage from hp and falling unconscious (or dying) so the first option is the one I think works.

Notwithstanding, awesome should always beat the rules.

Dale M
  • 210,673
  • 42
  • 528
  • 889
  • 3
    There's no call for arguing in the comments. There are two opposite answers: vote according to which you think is correct. – SevenSidedDie Mar 14 '16 at 18:38