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In D&D 5e, the Life Transference spell (XGtE, p. 160) heals an ally for twice the amount of damage it deals you (the caster). How much HP does the ally regain if the damage you roll is greater than your current HP?

Say you are at 5 HP. You roll 10 necrotic damage as a result of the spell, your HP goes to 0. Would the target of the spell heal for the full expected 20 HP, or only 10?

V2Blast
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automaton
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2 Answers2

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It would deal the full 10 points of damage, and heal the full 20 points to your target.

There are rules for how excess damage is treated, so that excess damage is (at least temporarily) tracked. The most clear rule for excess damage is the instant death rule:

Massive damage can kill you instantly. When damage reduces you to 0 hit points and there is damage remaining, you die if the remaining damage equals or exceeds your hit point maximum.

There is a similar part of the polymorph spell:

The target assumes the hit points of its new form. When it reverts to its normal form, the creature returns to the number of hit points it had before it transformed. If it reverts as a result of dropping to 0 hit points, any excess damage carries over to its normal form. As long as the excess damage doesn’t reduce the creature’s normal form to 0 hit points, it isn’t knocked unconscious.

Both of these show that the game does track damage beyond the amount that it would take to hit 0 hit points (for possible instant death in the first case, and to deal the excess to the creature's true form in polymorph). Since the full damage was dealt (even if the character's HP can't be negative), the full amount still gets doubled and applied as healing to the target.

Andrew
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    In that last example you gave, would the Aasimar Cleric really take half damage? Life Transference reads "....damage, which can't be reduced in any way..." – automaton Sep 29 '21 at 18:09
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    Ah, it appears to be errata. Didn't know since I was looking at an electronic resource. See https://media.wizards.com/2020/dnd/downloads/XGtE-Errata.pdf – automaton Sep 29 '21 at 18:18
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    @automaton Fair, I was going off of RAW in my physical books. I'll remove that last paragraph. – Andrew Sep 29 '21 at 18:19
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    These rules also support your claim: "For example, a cleric with a maximum of 12 hit points currently has 6 hit points. If she takes 18 damage from an attack, she is reduced to 0 hit points, but 12 damage remains." – Exempt-Medic Sep 30 '21 at 12:40
  • @Medix2 to keep the answer from getting long I put the rules but not the examples, I probably should have had both since it specifically references "damage remains" – Andrew Sep 30 '21 at 13:10
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I'd rule it'd only heal x2 the HP you have left.

In the spell's description, it states:

You sacrifice some of your health to mend another creature’s injuries. You take 4d8 necrotic damage, which can’t be reduced in any way, and one creature of your choice that you can see within range regains a number of hit points equal to twice the necrotic damage you take.

In your example, you only "take" 5 HP of damage before you become unconscious and have to start making death saving throws, etc.

I fully admit it's well open to interpretation of what constitutes "taken damage" but this seems to be a tit-for-tat exchange of HP ("transference" is right in the spell name) and allowing for HP being transferred when the caster is below zero is effectively transferring HP from nothing.

[addendum] - It is worth noting that nothing in my interpretation of the rules precludes dropping you down to zero HP, with the resultant death saving throws being required afterwards.

Σ of eDπ
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  • I'd agree that from reading the description, only x2 of the HP left would be healed. But on my table I'd rule that it heals the full x2 of the rolled damage. I guess if this spell is cast and it would reduce the player to 0 HP, they are in a dire situation, and I think the caster wants to feel heroic by "sacrificing" himself to heal another. So I'd be fine with beeing generous with my ruleing. But if a DM want to walk a finer line, then let the spell only heal the amount of HP that the caster had. – Simon Lang Sep 30 '21 at 11:59
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    Can you support this from RAW? – automaton Sep 30 '21 at 15:54
  • Per RAW, negative hit points only exist for purposes of instant death calculations. "Damage at 0 Hit Points. If you take any damage while you have 0 hit points, you suffer a death saving throw failure. If the damage is from a critical hit, you suffer two failures instead. If the damage equals or exceeds your hit point maximum, you suffer instant death." - Basically negative HP don't exist, so they can't be transferred, That's the RAW basis for my intepretation. – Σ of eDπ Sep 30 '21 at 17:30
  • Also not ruling this way opens things up to interesting "hacks" - With just 1HP remaining, do a Life Transference down to some amount that doesn't quite kill the character. Then have another character cast a cheap healing spell (Healing Word, say) as a readied action to get the char back to 1 HP and stable. Repeat as needed. This seems to get away with eliminating the biggest drawback of this spell. – Σ of eDπ Sep 30 '21 at 17:44