There are two different cases for a Vampire being in Mist Form.
- By volition: (Shapechanger ability)
- Via combat reduction to 0 hit points. (Misty Escape)
Shapechanger. If the vampire isn’t in sunlight or running water, it
can use its action to polymorph into a Tiny bat or a Medium cloud of
mist, or back into its true form.Misty Escape. When it drops to 0 hit points outside its resting place,
the vampire transforms into a cloud of mist (as in the Shapechanger
trait) instead of falling unconscious, provided that it isn’t in
sunlight or running waterWhile it has 0 hit points in mist form, it can’t revert to its vampire form, and it must reach its resting place within 2 hours or be destroyed.
My concern is that the Vampire being at 0 in mist form may be an edge case for the general 0 HP further damage rule.
Here is my line of thought. The Vampire takes on mist form and stays at zero hit points. It is "in transit" in mist form to its lair at a movement rate of 20.
MM p. 297
While in mist form, the vampire can’t take any actions, speak, or manipulate objects. It is weightless, has a flying speed of 20 feet, can hover … if air can pass through a space, the mist can do so without squeezing, and it can’t pass through water. It has advantage on Strength, Dexterity, and Constitution saving throws, and it is immune to all nonmagical damage, except the damage it takes from sunlight.
This leads me to believe that a party can destroy the Vampire without having to wait for two hours or put a stake into its heart when it arrives at its coffin/lair. The method is that the vampire in mist for can be destroyed by continuing to do magical damage until it fails 3 death saves.
Rule loophole: death saves may only be for characters, not monsters. It is unclear if monsters are utterly exempt from that provision, even though PHB 198 says.
the DM might have them fall unconscious and follow the same rules as player characters
As I read the description, the Vampire regeneration of 20 HP per round is constrained to its humanoid form, bat form, or it's misty form if it changed into that form by volition and while it has at least 1 HP.
A Cleric can typically move at 30, a Vampire's mist can move at 20. My instinct is that a party Cleric can cast Sacred Flame (Cantrip) round after round until a three death saves have been missed. Other sources of radiant or magical damage should work as well, as long at the damage being done is magical, to speed up the process.
– I chose Sacred Flame as it does radiant damage, which prevents regeneration in vampires, but that may be unnecessary.
Examples:
- Paladin's Holy Smite
- Warlock's Eldritch Blast
- Rogue's magical dagger
Presuming that the Party keeps doing damage, and the Vampire misses enough death saves before it floats beyond their reach and through that crack in the wall that the party can't get through, am I right?
Is the Vampire Destroyed?
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. (PHB, p. 197)
Question Restated
-
Does inflicting further damage on the misty 0 HP state allow the party to destroy the vampire?
-
Does the Vampire fail a death save as any other creature would, in the 0 HP misty state, when it takes any additional damage?
- Does the Vampire have an out that I don't see in the monster description or the rules?
A good answer will explain:
- Whether or not the Vampire is destroyed via this method
- If not, why not
Best Answer
Yes (probably)
Rules as Written, I think you can kill the 0-hit-point Misty Vampire by doing damage to it three times before it escapes to its resting place, or by doing massive damage to it (equal to or exceeding its maximum hit points).
But there is certainly room for disagreement, as the rules regarding creatures with 0 hit points are written in the context of creatures that are unconscious at 0 hit points, which the Misty form of the Vampire is not.
Honestly, I don't think the intent of the rules is to allow a Vampire to be destroyed in this way. It seems that the intent is that you have to follow it back to its resting place, drive a stake through its heart, and then destroy its body while it's paralyzed.
Rules around having Zero Hit Points
PHB p. 197 says
Creatures that take massive damage die outright.
Otherwise they fall unconscious but are dying -- they must make death saves to determine if they eventually stabilize or die outright.
There are three exceptions wherein a creature may be stable at 0 hit points -- still unconscious, but not needing to make death throws.
Note that in all cases here, a creature with 0 hit points is unconscious.
Normally there is no way for a creature to be at 0 hit points and still be conscious and taking actions. However, the Vampire is clearly an exception, based on the text of its Misty Escape feature. It is very unclear whether any of the usual rules that apply to unconscious creatures at 0 hit points also apply to Misty Vampires at 0 hit points.
So What Rules Apply to a Misty Vampire that is Stable and Conscious at Zero Hit Points?
The description of the Vampire clearly admits the possibility of doing damage to the Misty Form by magical means.
Taking Damage at 0 Hit Points (PHB p. 197):
And:
Note that a creature that takes damage while at 0 hit points that isn't enough to kill it outright remains at 0 hit points. 5e does not have a concept of negative hit points.
Two Ways to Kill the Zero-HP Vampire (RAW):
1) damage it three times, causing it to fail three death saving throws before it has a chance to stabilize or be stabilized by any of the means listed above
2) damage it once, for an amount that equals or exceeds its maximum hit points (perhaps a massive Paladin critical smite)
Caveats
On Misty Escape Re-stabilizing the Vampire
Clearly when the Vampire first drops to 0 hit points, the Misty Escape feature permits it to be stable and conscious where ordinarily it would be neither of those things.
If the Misty Escape feature triggers each time the Vampire takes damage while at 0 hit points, it could be argued that the feature stabilizes the Vampire each time.
However, the trigger for Misty Escape is that the Vampire drops to 0 hit points (outside its resting place). Getting hit while already at 0 hit points and remaining at 0 hit points does not constitute dropping to 0 hit points.
On Immunity to Failed Death Saving Throws
PHB. p. 198 says that Monsters can sometimes make Death Saving Throws:
Note that this is given as an option for a DM to make a creature more powerful than a normal monster that just drops dead at 0 hit points. But we already know that a Vampire is not a normal monster that just drops dead at 0 hit points. Its Misty Escape feature is a stronger feature than the standard Death Saves feature that prevents PCs from just dropping dead at 0 hit points. So this clause in the PHB doesn't really apply in this case.
However, I don't see anything here to suggest, whether the DM usually gives monsters death saves or not, that any monster should be immune to dying after suffering three failed death saves at 0 hit points.