Skip to main content




AC 16 (natural armor)

HP 130 (20d8 + 40; bloodied 65)

Speed 30 ft., fly 30 ft.

Proficiency +4; Maneuver DC 15

Saving Throws Int +8, Wis +7, Cha +7

Skills Deception +7, Insight +7, Perception +7, Persuasion +7, Religion +8

Damage Resistances fire, psychic, radiant

Condition Immunities charmed

Senses darkvision 60 ft., passive Perception 17

Languages Abyssal, Celestial, Infernal, telepathy 120 ft. 

Detect Alignment. The khalkos can detect the presence of creatures within 30 feet that have an alignment trait, and knows the alignment of such creatures. 

Magic Resistance. The khalkos has advantage on saving throws against spells and magical effects.

Psionic Spellcasting. The khalkos’s spellcasting ability is Intelligence (spell save DC 16). It can innately cast the following spells, requiring no components:

1/day each: alter self , plane shift (self only), telekinesis , teleportation circle


Claw. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 5 (1d4 + 3) slashing damage plus 10 (3d6) poison damage.

Chaos Pheromones. The khalkos emits a cloud of pheromones in a 20-foot radius. The cloud spreads around corners. Each non-khalkos creature in the area makes a DC 14 Intelligence saving throw . Creatures with an alignment trait make this save with disadvantage . On a failure, the creature is confused for 1 minute. It repeats the saving throw at the end of each of its turns, ending the effect on itself on a success. If the creature makes its saving throw or the condition ends for it, it is immune to Chaos Pheromones for the next 24 hours. 

Psionic Sting. The khalkos targets a creature within 30 feet, forcing it to make a DC 16 Intelligence saving throw . On a failure, the target takes 28 (8d6) psychic damage and is stunned until the end of its next turn. 


Brain Jab. Melee Weapon Attack: +7 to hit, reach 5 ft., one incapacitated creature with a brain and an Intelligence of 6 or higher. Hit: 5 (1d4 + 3) piercing damage, and the target becomes diseased with brain larvae. Once the khalkos has used this attack successfully, it can’t use it again for 24 hours.


Telekinetic Shield. When the khalkos is hit by an attack made by a creature that it can see or sense with its Detect Alignment trait, it gains a +4 bonus to AC against the triggering attack.


The khalkos starts combat by using Chaos Pheromones on clusters of enemies, and then uses Psionic Sting on either a creature with an alignment or a creature likely to fail an Intelligence saving throw. Once an enemy is stunned , the khalkos uses Brain Jab. The khalkos retreats once it has infected a target with brain larvae (possibly using plane shift if it hasn’t already today).

Disease: Brain Larvae

A khalkos can infect an intelligent creature with a horrifying disease , injecting khalkos larvae directly into the creature’s skull. While infected with this disease, the host undergoes the following changes:

Telepathy. The host gains telepathy out to a radius of 120 feet. Additionally, the host can telepathically communicate with the khalkos that infected it over any distance, as long as they are on the same plane.

Trust. Whenever a khalkos makes a Charisma check to convince the host of its good intentions, it does so with advantage . If it succeeds, the host becomes friendly to it no matter its previous attitude. 

After 10 (3d6) days, the host develops a splitting headache and is incapacitated for 24 hours. At the end of this time, the host dies. If the host has an alignment trait, 2 or 3 khalkos spawn burst out of the host’s skull after 1 round.

Greater restoration or a similar spell cast with at least a 5th-level spell slot is required to kill the brain larvae and remove the disease.

Legends and Lore

With an Arcana or Religion check, characters can learn the following:

DC 15 An ancient book, purportedly written by a refugee from another reality, describes a species of intelligent, wasp-like creatures that parasitically prey on angels and other planar beings.

DC 20 A khalkos is a wasp-like aberration. It exudes a cloud of pheromones that maddens everyone nearby, and it implants creatures with skull-exploding larvae.


Khalkoi, more commonly known as mind wasps, are parasitic predators that feed on the cosmic principles of good and evil, law and chaos. They conquer reality after reality, leaving behind deserted heavens and dead gods as they rob worlds of divine magic.

A khalkos is humanoid in shape with an inexpressive wasp face. It is able to disguise itself psionically in order to infiltrate sacred or profane places, dooming them to destruction. 

Parasitic Life Cycle. Adult khalkoi implant their larvae into the brains of intelligent creatures. A parasitized victim comes to see every khalkos as an ally to be trusted, and may even help a khalkos implant its eggs in other victims. When khalkos larvae are ready to be born, they burst from the skull of their host. As the headless victim collapses to the ground, the khalkos larvae—now independent khalkos spawn —fly away to search for new victims.

 Although khalkos larvae can infect any intelligent creature, they prefer hosts that are cosmically aligned: archpriests and saints, angels and devils, and even gods. Only in such hosts can khalkos larvae consume the divine magic they need to perpetuate their horrific life cycle. Khalkos spawned from an aligned creature begin growing into adult khalkoi immediately, reaching maturity in a few days. Khalkos that hatch from unaligned creatures must consume many humanoid creatures, over a period of months or years, before they mature.

Existential Threat. A khalkos can sense cosmic power as a spider senses a tremor in its webs. The battles of warring pantheons, or mighty deeds performed by celestial or fiendish champions, can attract their attention to a heretofore-overlooked planar realm.

Usually, only a single khalkos travels to a newly discovered world. With mastermind intelligence and mind-clouding psionic powers, it infiltrates a temple or cult. Finally, it targets a divinely-empowered priest or minor fiend, hijacking its body to serve as the breeding ground for its eggs. Soon, one khalkos becomes a swarm of khalkoi that immediately set their sights on bigger game.

Fight or Flight. A few worlds have successfully fought off a khalkos invasion. To win such a war, powerful cosmic entities must be aided by unaligned heroes: warriors, spellcasters, and other adventurers who don’t inherit their power from cosmic principles but who are willing to fight for them nonetheless. 

Other worlds have survived the khalkos threat by avoiding detection. Some dimensions have constructed vast psychic barriers or concluded divine treaties to limit the power of deities and fiends. If these magical protections are violated, such worlds risk unwelcome attention.


1 Using alter self to infiltrate a group as a low-ranking member

2 Using alter self to infiltrate a group, taking the form of a high-ranking member that it has killed

3 Attacking, determined to infect a certain person with khalkos larvae

4 Using alter self and asking questions about local groups

5 Ritually casting teleportation circle as part of a year-long effort to make a permanent circle

6 Scouting for a larger group; has big plans and wants to eliminate anyone who could upset them


1-2 A corpse in a pool of blood, its head exploded

3-4 People acting strangely, insisting that you visit a friend of theirs who will make everything clear

5 What appears to be a dead, foot-long wasp

6 A faint, intoxicating scent in the air


Khalkoi haven’t discovered our reality yet. If they do, they will probably target Hell, the Abyss, or the planar realm of a god, or perhaps infiltrate a religious organization on the Material Plane.

CR 5–10 khalkos ; 3 to 5 khalkos spawn ; 2 swarms of khalkos spawn

CR 11–16 khalkos with parasitized cambion , couatl , high priest , or unicorn ; khalkos with 2 parasitized bearded devils or priests

Treasure 6 beads of force

CR 17–22 2 khalkos ; khalkos with 4 to 6 khalkos spawn

Treasure strangely proportioned black metal helm (acts as crystal ball when worn), cubic gate

Monster Type Description

Aberrations are unnatural beings that don’t belong to this plane of existence. Many aberrations are telepathic and use a mental power known as psionic power instead of magic. An aboleth is an aberration.