Ose

Large fiend (demon, shapechanger), chaotic evil

Armor Class 19 (natural armor)

Hit Points 199 (19d10 + 95)

Speed 40 ft., climb 40 ft., fly 60 ft. (hover)

STR 23 (+6) · DEX 16 (+3) · CON 21 (+5) · INT 20 (+5) · WIS 18 (+4) · CHA 22 (+6)

Saving Throws Dex +9, Con +11, Int +11, Wis +10, Cha +12

Skills Arcana +11, Deception +12, Insight +10, Perception +10, Stealth +9

Damage Resistances cold, fire, lightning; bludgeoning, piercing, and slashing from nonmagical attacks

Damage Immunities poison

Condition Immunities charmed, poisoned

Senses truesight 120 ft., passive Perception 20

Languages Abyssal, Celestial, Common, telepathy 120 ft.

Challenge 18 (20,000 XP)

Traits

Shapechanger. Ose can use his action to polymorph into a Large leopard, a Medium or Small humanoid, or back into his true hybrid form. Other than size, his statistics are unchanged. Equipment he is wearing or carrying isn’t transformed. He reverts to his true form if he dies.

Legendary Resistance (3/Day). If Ose fails a saving throw, he can choose to succeed instead.

Magic Resistance. Ose has advantage on saving throws against spells and other magical effects.

Magic Weapons. Ose’s weapon attacks are magical.

Perfect Transmogrification (Recharge 5–6). As part of a spell or ability that forces a saving throw, Ose can transform up to three creatures he can see within 60 feet. Each creature must succeed on a DC 20 Wisdom saving throw or be permanently transformed as though by true polymorph (PHB, p. 283/335). While transformed, the creature’s memories and personality are altered to suit its new form. A creature can repeat the saving throw when it finishes a long rest, ending the effect on a success. The effect also ends if Ose dies or dismisses it.

Innate Spellcasting. Ose’s innate spellcasting ability is Charisma (spell save DC 20, +12 to hit with spell attacks). He can innately cast the following spells, requiring no material components:

At will: detect thoughts (PHB, p. 231/262), disguise self (PHB, p. 233/262), minor illusion (PHB, p. 260/298), suggestion (PHB, p. 279/321)

3/day each: confusion (PHB, p. 224/253), invisibility (PHB, p. 254/289), major image (PHB, p. 258/295), mass suggestion (PHB, p. 258/296), phantasmal killer (PHB, p. 265/304)

1/day each: dominate monster (PHB, p. 235/265), maze (PHB, p. 258/296), true seeing (PHB, p. 284/336), weird (PHB, p. 288/341)

Actions

Multiattack. Ose makes three Leopard Claw attacks.

Leopard Claw. Melee Weapon Attack: +12 to hit, reach 10 ft., one target. Hit: 11 (2d6 + 6) slashing damage plus 13 (3d8) psychic damage.

Maddening Truth (Recharge 4–6). Ose speaks a fragment of terrible lore. Each creature of Ose’s choice within 30 feet that can hear him must make a DC 20 Wisdom saving throw. On a failure, a creature takes 32 (5d12) psychic damage and is stunned until the end of Ose’s next turn. On a success, the creature takes half damage and isn’t stunned.

Bonus Actions

Revelatory Whisper (Recharge 4–6). Ose targets one creature he can see within 60 feet, forcing it to make a DC 20 Wisdom saving throw. On a failure, the target takes 22 (4d10) psychic damage and is frightened of Ose until the end of its next turn. On a success, the target takes half damage and isn’t frightened.

Reactions

Paradoxical Shift. When a creature Ose can see attacks him, Ose can impose disadvantage on that attack roll.

Legendary Actions

Ose can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. Ose regains spent legendary actions at the start of his turn.

Attack. Ose makes one Leopard Claw attack.

Maddening Whisper (Costs 2 Actions). Ose uses Revelatory Whisper.

Warp Perception (Costs 3 Actions). Ose casts an at-will spell.

Lore

A spirit in leopard form who serves as an enlightened tutor of the liberal arts, yet wields a terrifying power to shatter sanity—masterfully warping reality and planting in victims a brief but absolute conviction of their own grandeur.

The name of the demon in question appears in historical manuscripts under several phonetic and orthographic variants: Ose, Oze, Oso, Voso, and Ozemos. Such linguistic variability is typical of demonological treatises, which were repeatedly recopied, translated, and adapted by different authors over the centuries, from Latin originals to French and English Renaissance versions. The name’s meaning is twofold: on one side it comes from the Latin “os,” meaning “mouth,” pointing to Ose’s role as oracle, mentor, and bearer of hidden truths; on the other, from “osor,” translated as “hater,” expressing his destructive, harmful nature—his tendency to induce madness and erase a victim’s identity. Both senses surface in his power to deliver truth while simultaneously shattering the mind.

Ose is first described as manifesting as a large leopard or panther, a form rich in symbolism. In medieval and apocalyptic texts the leopard was linked to heresy, deceit, and animal cunning; an unnatural hybrid, it symbolized sin and the “Beast.” After this initial feline guise, Ose takes on a humanoid form—an adult man, a child, or a scholar with a book. In well-known nineteenth-century artwork he often appears as a man-like monster with the head of a leopard: a fusion of high intellect and animal aggression mirrored in both his symbolism and behavior.

From Demonic Bestiary 5E, p. 80 · Fern Flower Press