A mineshaft full of withered corpses, their faces contorted in abject terror. A vile cult torn apart by ferocious infighting and violent paranoia. These scenes and similar events of mass hysteria are the hallmark of the fell-ordalius, an unseen force that drives souls into a self-destructive downward spiral of fear and desperation. An invisible threat of a diabolical nature, the fell-ordalius is the voice of doubt in the back of one’s mind, the gnawing fear that eats at the heart of every creature with hopes and dreams. A formless being of smoke and fear, the fell-ordalius’s presence is felt long before it is perceived as it stalks its victims. It never makes a sound, a silent witness to the madness inspired by its presence.


Small aberration, neutral evil

Armor Class 18 (natural armor)
Hit Points 162 (25d6 + 75)
Speed fly 40 ft. (hover)

1 (-5) 22 (+6) 16 (+3) 8 (-1) 25 (+7) 10 (+0)

Saving Throws Dex +12, Int +5, Wis +13
Skills Insight +13, Perception +13, Stealth +12
Damage Resistances bludgeoning, piercing, and slashing
Condition Immunities charmed, exhaustion, frightened, grappled, paralyzed, petrified, poisoned, prone, restrained, stunned, unconscious
Senses blindsight 60 ft., passive Perception 23
Languages Fell-tongue
Challenge 17 (18,000 XP)


Invisibility. The fell-ordalius is invisible.

Living Nightmare. As a bonus action, the fell-ordalius can emit a cloud of hallucinogenic fumes in a 60-foot-radius sphere centered on it. The sphere moves with the fell-ordalius and last until the fell-ordalius ends the effect as a bonus action. When a creature enters the area for the first time on its turn or starts its turn there, it must succeed on a DC 21 Constitution saving throw or begin to hallucinate for as long as it remains within the area. While hallucinating, the creature is frightened of everything it can perceive (including sounds, sensations, and objects). This lasts until the effect ends for the creature or it ends its turn outside the effect’s area. A creature that spends 1 continuous minute frightened by this effect immediately dies of fright. Once a creature has succeeded on a saving throw against this effect, it is immune to this effect for 24 hours.

Shroud Form. The fell-ordalius can enter a hostile creature’s space and stop there. It can move through a space as narrow as 1 inch wide without squeezing.


Instill Doubt. The fell-ordalius inflicts a creature it can see within 60 feet with crippling doubt. Until the start of its next turn, when the creature would roll a 6 or higher on an attack roll or ability check, it instead rolls a 5.

Violent Paranoia. The fell-ordalius deals 21 (6d6) psychic damage to each frightened creature within 120 feet of it. If an affected creature is not aware of the fell-ordalius, it must succeed on a DC 21 Wisdom saving throw or attribute the effect to the nearest creature it can perceive.

Ref: TPKB1 p113