In 5e D&D and Grim Hollow, how does the Specter transformation affect a human PC in regards to the 'undead' characteristics and spells?

Question

In 5e D&D + Grim Hollow, how does the 'undead' characteristic given to a human PC change how some spells, items or abilities affect him?

Grim Hollow is a dark fantasy content book and can be found here. Page 95 of the book handles the Specter transformation.

The relevant Grim Hollow's Specter transformation text is as follows:

You become undead in addition to any other creature types you are. [...] Spells that affect humanoids still affect you. However, you're immune to effects that only affect a creature of your new type of a specific CR. [...]

Will a cleric's Cure Wounds spell affect the Specter human with the 'dual' humanoid/undead type?

The spell doesn't effect undead creatures, but what about a humanoid/undead with the specific features mentioned above from Grimbollow? I read about the Centaurs' dual creature type (but not sure if it was changed to only 1 in the end) but I couldn't find an answer that seemed to satisfy the question.

Answer 1

Cure Wounds doesn’t affect you

Specific trumps general.

The base rule is from the Monster Manual p.5:

TYPE

A monster's type speaks to its fundamental nature. Certain spells, magic items, class features, and other effects in the game interact in special ways with creatures of a particular type. For example, an arrow of dragon slaying deals extra damage not only to dragons but also other creatures of the dragon type, such as dragon turtles and wyverns.

The game includes the following monster types, which have no rules of their own.

The next most specific rule is that "Spells that affect humanoids still affect you"

The most specific rule comes from the specific spell text.

Cure Wounds says, "This spell has no effect on undead or constructs." It has no rules about humanoids. It does have special rules about undead - it doesn't affect them, so it doesn't affect you.

If we contrast this with spells that do have special rules about humanoids like Hold Person, which says, "Choose a humanoid that you can see within range." This spell will affect you because it specifically affects humanoids.

Because the starting point is that monster types "have no rules of their own", the correct reading is that effects affect all creatures unless they are ruled out. So, as written, any effect affects you unless:

1. It doesn't affect humanoids, or
2. It doesn't affect undead unless it specifically affects humanoids.

That may not be what the author intended but that's what they wrote.

Answer 2

It appears to me that the second sentence from your quotation answers the question:

Spells that affect humanoids still affect you.

Therefore you could use Cure Wounds, or even Reincarnate on such a Specter PC, because those spells do affect humanoids, even if they don't affect undead creatures.