[RPG] Can you cast Hellish Rebuke as a reaction to damage that reduces you to zero hit points


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)

Best Answer

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.