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Cult Mastermind

Medium humanoid (any race), any chaotic or evil alignment

Armor Class 13 (16 with mage armor)

Hit Points 81 (18d8)

Speed 30 ft.

10 (+0) 16 (+3) 10 (+0) 16 (+3) 15 (+2) 20 (+5)

Saving Throws Wis +6, Cha +9; –2 on saving throws against confusion, insanity, and madness

Skills Deception +9, History +6, Yog-Sothothery +6

Damage Resistances damage from spells

Senses truesight 30 ft., passive Perception 12

Languages any four languages

Challenge 12 (8,400 XP)

Special Traits

    • Innate Spellcasting. The mastermind’s spellcasting ability is Charisma (spell save DC 17). It can innately cast the following spells:
      • At will: detect evil and good, disguise self, mage armor, phantasmal killer (can’t target same creature again for 24 hours)
      • 1/day each: cursed slumber, eyebite, finger of death, glibness, plane shift, teleport
    • Secret of Dimensions Unfathomed. When the mastermind damages a target with a warlock cantrip, the target must make a DC 17 Charisma saving throw. On a failed save, the target teleports to an unoccupied space of the mastermind’s choice that it can see and that isn’t hazardous to the target within 10 feet of the target’s current location.
    • Spellcasting (Pact Magic). The mastermind is an 18th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 17, +9 to hit with spell attacks). It knows the following warlock spells:
      • Cantrips (at will): eldritch blast (range 300 ft., pushes target 10 feet away), minor illusion, poison spray, prestidigitation
      • 1st–5th level (4 5th-level slots): banishment, bestow curse (1/day), blink, charm person, counterspell, dimension door, dispel magic, fly, greater invisibility, hold monster, identify, scrying, suggestion


    • Multiattack. The mastermind casts a spell (expending a use or spell slot as normal). It then either casts a cantrip or makes a dagger attack.
    • Dagger. Melee or Ranged Weapon Attack: +7 to hit, reach 10 ft. or range 40/120 ft., one target. Hit: 5 (1d4 + 3) piercing damage.


  • Counterspell. The mastermind knows counterspell, which it can cast as a reaction.
  • Interdimensional Escape. When the mastermind is hit by an attack or included in a spell or effect, it can cast blink as a reaction, expending a spell slot as normal. It immediately roll a d20, becoming ethereal and negating the triggering attack, spell, or effect on a result of 11 or higher. The spell functions normally thereafter.


Cult masterminds lead cults to exploit grand eldritch pacts, generally using the connections a city offers. They often worship Hastur, the King in Yellow, Nyarlathotep, Tsathoggua, and Yog-Sothoth.

Section 15: Copyright Notice

Sandy Petersen’s Cthulhu Mythos, © 2018, Petersen Games; Authors: Sandy Petersen, David N. Ross, James Jacobs, Arthur Petersen, Ian Starcher.