Does repeatedly using the Long Death monk's Touch of Death feature let you stack up temporary hit points?

Question

I'm building a ghostwise halfling monk of the Way of the Long Death, and was thinking about the 3rd-level Touch of Death feature (SCAG, p. 130):

When you reduce a creature within 5 feet of you to 0 hit points, you gain temporary hit points equal to your Wisdom modifier + your monk level (minimum of 1 temporary hit point).

Is it legal to kind of 'whack-a-mole' some monster... say a goblin? In other words, knock it out to 0 hp, stabilize it back to 1, hit it again, rinse and repeat to stack loads of temporary hit points?

Answer 1

Sorry but...

Temporary Hit Points Do Not Stack

If you have temporary hit points and receive more of them, you decide whether to keep the ones you have or to gain the new ones. For example, if a spell grants you 12 temporary hit points when you already have 10, you can have 12 or 10, not 22.

PHB198

So, the best I can offer you is this. You carry around a goblin, hogtied, in your backpack. After every fight, you punch him unconscious (You have to explicitly declare you are doing this...normally a monster reduced to 0hp dies instantly and cannot be stabilized. See PHB 198) to top off your pool of temporary hit points. You can't stack up a pile...but you have have a THP dispenser you can lug around with you to make sure you regularly stay at WIS+Level Temporary HP in between fights.

(Disclaimer: guildsbounty is not responsible for any alignment shifts you may incur by following this advice to torture goblins, or for extreme social ostracism due to the horrific smells emanating from your pack)

Answer 2

Temp HP don't stack

Tormenting a captive goblin in this way wouldn't get you as much as you think. Temp HP doesn't stack, which means that no matter how many times you do it, you still only have Monk lvl+wismod, and those temp hp will expire after a while.

Admittedly, if you don't like that time limit, you could decide to bring along an eminently punchable goblin to regularly beat into bloody unconsciousness and then drag back from the brink of death as your temp HP expires throughout the day, so that you'd start every fight topped up. Nothing stops you. Honestly, that sounds like a fantastic roleplaying hook, and interesting insight into just how far down the path of cold cruelty your character is willing to go to get an advantage in a fight.

Answer 3

No; you can't stack temporary HP like this, because gaining new temporary HP (potentially) replaces your existing ones.

Per the basic rules:

If you have temporary hit points and receive more of them, you decide whether to keep the ones you have or to gain the new ones. For example, if a spell grants you 12 temporary hit points when you already have 10, you can have 12 or 10, not 22.