The spirit of the reward is that the body can recover from any damage as long as the brain and heart continue to function and remain intact.
Monsters with this reward can't drown; although the brain and heart will stop receiving oxygen, they will keep the monster alive (if, potentially, in terrible agony). Decapitation and being set on fire can both result in death, however -- decapitation if the brain is directly physically affected, and fire if the heart or brain receive damage.
The 'or' does not signify choice between organs - however, it's completely fine to avoid taking the reward altogether, if someone prefers.
no subject
The spirit of the reward is that the body can recover from any damage as long as the brain and heart continue to function and remain intact.
Monsters with this reward can't drown; although the brain and heart will stop receiving oxygen, they will keep the monster alive (if, potentially, in terrible agony). Decapitation and being set on fire can both result in death, however -- decapitation if the brain is directly physically affected, and fire if the heart or brain receive damage.
The 'or' does not signify choice between organs - however, it's completely fine to avoid taking the reward altogether, if someone prefers.