Does a humanoid possessed by a ghost register as undead to a paladin's Divine Sense?

Question

A Ghost (MM, p. 147) can possess a humanoid as per their Possession action:

Possession (Recharge 6). One humanoid that the ghost can see within 5 feet of it must succeed on a DC 13 Charisma saving throw or be possessed by the ghost; the ghost then disappears, and the target is incapacitated and loses control of its body. The ghost now controls the body but doesn't deprive the target of awareness. The ghost can't be targeted by any attack, spell, or other effect, except ones that turn undead, and it retains its alignment, Intelligence, Wisdom, Charisma, and immunity to being charmed and frightened. It otherwise uses the possessed target's statistics, but doesn't gain access to the target's knowledge, class features, or proficiencies. [...]

A paladin's Divine Sense (PHB, p. 84) says:

The presence of strong evil registers on your senses like a noxious odor, and powerful good rings like heavenly music in your ears. As an action, you can open your awareness to detect such forces. Until the end of your next turn, you know the location of any celestial, fiend, or undead within 60 feet of you that is not behind total cover. You know the type (celestial, fiend, or undead) of any being whose presence you sense, but not its identity (the vampire Count Strahd von Zarovich, for instance). [...]

If a humanoid was possessed by a ghost, then a paladin were to enter the room and use their Divine Sense, would the humanoid register as undead (or the undead nature of the ghost still otherwise show up on the paladin's "radar", such as detecting undead within the humanoid or something like that) or would the possession effectively render the ghost immune to being detected by Divine Sense?

Answer 1

RAW indicates No.

The phrase

the ghost then disappears

in the description of Possession, together with the following listing of untargetability indicated that the ghost for the duration of the effect does not exist as an independent, locatable entity distinguishable from its host. Therefore, because the host is not undead, and the ghost does not have a location (as written, it disappeared), the Divine Sense can't locate the creature.

In a different interpretation, the ghost could be said to be inside the human in question. However, in this case, RAW still would prohibit it, because Divine Sense allows you to

know the location of any celestial, fiend, or undead within 60 feet of you that is not behind total cover.

(Emphasis mine) Being inside an opaque object, the human body, certainly would count as total cover, and therefore stop the detection.

Answer 2

RAW states no.

From the description given for the ghost entry in the MM (Emphasis mine):

The ghost can't be targeted by any attack, spell, or other effect, except ones that turn undead, and it retains its alignment, Intelligence, Wisdom, Charisma, and immunity to being charmed and frightened.

Since the Divine Sense is not a turning effect, merely a sensing one, it can't detect a ghost in possession of someone else.

Answer 3

I would say: sure

Essentially, the spirit within the body is being overpowered by a second spirit, the second spirit being undead.

The ghost description states...

Possession (Recharge 6). One humanoid that the ghost can see within 5 feet of it must succeed on a DC 13 Charisma saving throw or be possessed by the ghost; the ghost then disappears, and the target is incapacitated and loses control of its body.

Personally, I take that to mean it doesn't exist as a singular entity that can be seen or interacted with on the map. It is now a spirit within a possessed body as opposed to a "ghost".

The possession states...

The ghost can't be targeted by any attack, spell, or other effect, except ones that turn undead, and it retains its alignment, Intelligence, Wisdom, Charisma, and immunity to being charmed and frightened.

However, divine sense states...

Until the end of your next turn, you know the location of any celestial, fiend, or undead within 60 feet of you that is not behind total cover.

Divine sense is basically enhanced perception as opposed to a targeted attack, spell, or effect. The paladin is now aware of more than they were, but they aren't attacking or targeting anything per say. I'm the Player's Handbook, it shows up under Class Features and is treated differently than a spell or targeted effect.

As for total cover... (Taken from the Cover subsection under Combat chapter 9 of the Player's Handbook via D&D Beyond phone app)

Total Cover A target with total cover can't be targeted directly by an attack or a spell, although some spells can reach such a target by including it in an area of effect. A target has total cover if it is completely concealed by an obstacle

A ghost could take total cover behind a body which is different from possessing a body. In a possession, body and soul are one. The soul isn't hiding in the body, it is inhabiting and controlling the body, hence it can still be hit with Turn Undead.

As a DM, if this happened in my game, I would say the paladin senses an undead presence, but it is diluted in some way. Not a pure undead since it is "hiding" in the possessed body, but still undead by its own nature. I would play it that the possession denies any targeted effect since it is "hiding" in a body, but it is still in fact undead and could still be perceived as such. Kinda up to the DM though.

Answer 4

Divine Sense will detect the ghost

If the ghost can be affected by a cleric's Turn Undead, then it must be hiding inside the body of the target.

The rule that says the ghost can't be targeted by any attack, spell or other effect doesn't come into play since divine senses doesn't target anything, it detects.

Divine Sense doesn't tell you that a creature is undead (or a celestial or a fiend). It tells you the location of such creatures. The paladin would know that there is an undead at the same location as the humanoid they are currently possessing.

The ghost does not have total cover while hiding inside their target, as the rules do not state that it does. Even if you consider that the ghost is "inside" of the humanoid target, that isn't the same kind of inside as a creature hiding inside of a locked room. The ghost is infusing itself into the target. They overlap rather than the ghost using the body as a literal hiding place. On top of that, the rules for cover clearly state:

Walls, trees, creatures, and other obstacles can provide cover during combat, making a target more difficult to harm. A target can benefit from cover only when an attack or other effect originates on the opposite side of the cover.

The Divine Sense ability isn't originating from the opposite side of their "cover". For that the be true the ghost would need to be hiding directly behind their possessed humanoid.

Answer 5

By RAW, Yes

TLDR: In order for the Ghost to be applicable to be effected by Turn Undead and Dispel Evil and Good, which their possession ability explicitly states that they are, then they by definition become applicable to be detected via Divine Sense and Detect Evil and Good. Via the fact that neither features or spells require you to target the Ghost directly, which is what possession protects the Ghost from. You can't have one without the other without inserting effects that possession doesn't grant.

Divine Sense and Detect Evil and Good have three requirements. Is the creature of a certain type? Are they in range? Are they not behind total cover? (or metal/stone/dirt in Detect EoG case)

Divine Sense

The presence of strong evil registers on your Senses like a noxious odor, and powerful good rings like heavenly music in your ears. As an action, you can open your awareness to detect such forces. Until the end of your next turn, you know the location of any Celestial, fiend, or Undead within 60 feet of you that is not behind total cover.

Detect Evil and Good

For the duration, you know if there is an aberration, celestial, elemental, fey, fiend, or undead within 30 feet of you, as well as where the creature is located. Similarly, you know if there is a place or object within 30 feet of you that has been magically consecrated or desecrated.
The spell can penetrate most barriers, but it is blocked by 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt.

Presuming a undead Ghost has possessed a humanoid and within range, then the only question remaining is, do they have full cover or not? The answer is no.

The ghost can't be targeted by any Attack, spell, or other Effect, except ones that turn Undead, and it retains its Alignment, Intelligence, Wisdom, Charisma, and immunity to being Charmed and Frightened. It otherwise uses the possessed target's Statistics, but doesn't gain access to the target's knowledge, Class Features, or Proficiencies.

The ghost disappears and cannot be targeted. This is not full cover, and at no point does the ability says or suggest that it is. The Ghost just cannot be targeted, and any damage or effect hit the host rather then the Ghost. (i.e. from indirect means, such as an AoE)

However, the possession ability explicitly states that the Ghost can still be affected by Turn Undead and Dispel Evil and Good.

Turn Undead

As an action, you present your holy symbol and speak a prayer censuring the undead. Each undead that can see or hear you within 30 feet of you must make a Wisdom saving throw. If the creature fails its saving throw, it is turned for 1 minute or until it takes any damage.

Dispel Evil and Good

Break Enchantment. As your action, you touch a creature you can reach that is charmed, frightened, or possessed by a celestial, an elemental, a fey, a fiend, or an undead. The creature you touch is no longer charmed, frightened, or possessed by such creatures.

Meaning in the case of Turn Undead, the Ghost must be both present and able to see and hear the caster, as possession doesn't change the Ghost's creature type, thus it must still be an undead. Dispel Evil and Good only requires the Ghost to be present and of the Undead creature type.

Since we know the Ghost is in fact applicable to the effects of both Turn Undead and Dispel Evil and Good, when know for a fact that the Ghost retains its creature type and is still present even after disappearing during possession. The Ghost disappears and is no longer visible as opposes to the Invisible status. This is not non-existence.

Conclusion: As I have explained, Turn Undead requires the Ghost to still be present, in range and of the same undead creature type during possession in order to effect the Ghost, which they are. Possession doesn't grant the Ghost full cover, or any cover of any kind, but rather the ability to no longer be targeted.

However, Turn Undead, Dispel Evil and Good, Divine Sense and Detect Evil and Good DO NOT TARGET THE GHOST, nor do the latter effect the Ghost directly in any way, shape or form. And so therefor possession in not applicable as a defense against these spells and features.

Thus you can absolutely detect when a humanoid is possessed by a Ghost with Divine Sense.

Answer 6

I would say RAW says that you can detect it, but I might be misinterpreting the word “disappears.”

People are stating that the ghost exists inside the human being, as if eaten by it, but I do not think that RAW supports that that’s what has happened. Given that the ghost disappears within 5 feet of the creature and reappears within 5 feet of the creature, my best guess is that it is in some sense existing in a location outside of that creature, controlling it like a puppeteer controlling a marionette, it just happens to be an invisible and intangible puppeteer. Invisibility is well-defined in RAW but does not quite get into that “everything passes through it” intangibility a la Project Image. Whether the ghost must keep line-of-sight with the target is less clear to me, but I don't think it does (it is not mentioned that it must reappear in a location within line-of-sight).

If that interpretation is correct then you can sense it normally with Divine Sense unless the ghost happened to see that sort of thing coming and hid 5 feet away from the possessed character, behind total cover. A very clever ghost might be able to pass through a wall within 5 feet right before Divine Sense, to evade it, but they would probably need advance warning to do so.

I will also argue against myself here: in another circumstance, Find Familiar says that a familiar dropped to 0hp “disappears” similarly, but we would not in normal interpretations of RAW say that maybe you can still communicate with it because “it’s still within 100 feet of you, it’s just intangible” the way that this answer is treating “disappears.”

Answer 7

I would say it would not show up as undead with a paladin Divine Sense, but would if the spell Detect Evil and Good was cast.