D&D: Astral Madness & Mutant-Zombie Ghouls

I'm going through an editing process right now for a new adventure I hope to publish here in the next couple of weeks called "The Fall of Cahokiantep".  To quote the introduction:

The purpose of this adventure is twofold.  It introduces the city of Cahokiantep as an adventure location, and it provides a bridge from a traditional swords-and-horses style roleplaying campaign to plane-hopping fantasy with elements inspired by science fiction.

"The Fall of Cahokiantep" is intended as the first part of a trilogy, but as of this writing all I have for the next part is a high concept.  I've no clue at all how the thing is going to end.

Crypt of Shadows # 5 (Sep 1973).

One of the signature elements of the new adventure is widespread exposure to unfiltered energy from the Astral Realm.  This has deleterious effects on the unprotected human mind, requiring the development of a new disease and some basic ideas about what that disease does as it progresses.  This particular story is a kind of zombie story--I've been working on the basic ideas since "24 Causes of the End of the World"--thus Astral Madness.

From "The Fall of Cahokiantep":

Each member of the party must make a DC 12 Wisdom or Constitution saving throw (their choice); Chaotic Neutral PCs make this save with disadvantage.  On a failed save, PCs are afflicted with the first stage of Astral Madness (see below).  Each time the party takes a long or a short rest, the PCs must again save against Astral Madness, with additional failed saving throws pushing them further into the disease’s grip.

 -- A DC 10 Intelligence check (Arcana or Nature) reveals that Astral Madness is caused by some kind of extra-planar energy.  A DC 12 check reveals that there must be at least one planar rift open somewhere in the city.

 -- A DC 13 Intelligence (Arcana) or Wisdom (Medicine) check reveals that the effects of Astral Madness are similar to the effects of a curse.  The disease can be countered with a Remove Curse or Lesser Restoration spell.

 -- A DC 15 Intelligence (Arcana or Religion) check reveals that the energies that cause Astral Madness are native to the Astral Realm, the plane of celestials, deities, and other extra-planar entities.  The disease’s effects can be prevented long-term by the use of a Protection from Energy spell or by a magic item that grants the effects of this spell to its wearer.

Astral Madness

Astral Madness manifests itself through physical and psychic symptoms brought on as a result of unprotected exposure to the energies of the Astral Plane.  The disease has four stages.

Initial stage—Astral Confusion. The subject has trouble telling what’s real from what’s not real.  As a result, he/she can no longer tell right from wrong can no longer make non-lethal attacks.  He/she also has disadvantage on all saving throws.

Second stage—Physical Confusion.  The subject grows fangs and claws.  He/she can no longer use traditional weapons but can instead use its claws as finesse weapons, which deal 1d6 points of damage each.  The subject is proficient with its claws.  The subject’s alignment also changes to Chaotic Neutral.

Third Stage—True Astral Madness.  The subject becomes a mutant-zombie ghoul.  It loses control of its actions and immediately attacks the closest living creature not affected by Astral Madness.

Final Stage—Death.  The subject dies.  Only a True Resurrection spell can restore the subject to life as anything other than a mutant-zombie ghoul.

Mutant-Zombie Ghouls

These creatures are mechanically similar to common undead ghouls save that they are still technically alive.  Exposure to the bizarre energies of the Astral Plane has infected them both physically and psychically, however, triggering the growth of fangs and claws as well as an unnatural hunger for human flesh.  In lieu of an undead ghoul’s usual Claw attack, mutant-zombie ghouls have the following:

Melee Attack—Claw: +4 to hit, reach 5 ft., one target. Hit: 7 (2d4 + 2) slashing damage, and the target must succeed on a DC 10 Wisdom saving throw or be paralyzed for 1 minute.  During paralysis, the target falls prone and shakes uncontrollably.  The target can repeat its saving throw at the end of each of its turns, ending the effect on a success.

Mutant-zombie ghouls also have the following ranged attack and reaction, each of which they can use once per day:

Ranged Attack—Glare of Madness: As a bonus action, the mutant-zombie ghoul targets one creature it can see within 60 feet.  The target must succeed on a DC 10 Wisdom saving throw or be charmed until the end of the mutant-zombie ghoul’s next turn.  While charmed, the target can still take actions, but it cannot attack the mutant-zombie ghoul or its allies, and it has disadvantage on all saving throws.

Melee Attack (Blast)—Psychic Feedback: When the mutant-zombie ghoul is reduced to 0 hit points, its death triggers a psychic feedback loop.  Living creatures within 10 ft. must make a DC 12 Wisdom or Constitution saving throw (target’s choice) or take 2d6 psychic damage.

Since mutant-zombie ghouls are not undead, they have neither an undead ghoul's strengths nor weaknesses.  For example, they are not affected by a Cleric's Turn Undead, but they are also not immune or resistant to poison.  Mutant-zombie ghouls have resistance (not immunity) to charm and exhaustion, and they are also resistant to psychic damage and have advantage on saving throws against psychic effects.  Like undead ghouls, mutant-zombie ghouls are Challenge Level 1 creatures.  Because of their additional attacks, they are worth 250 xp each.

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"The Fall of Cahokiantep" will be out (free) in a week or two.  If you've got thoughts on any of this stuff, now's your chance to have some input.  Thanks in advance.