Vitreous Choirmaster

Medium aberration (crystalline, psionic), lawful evil · CR 15

by Glasswright Voss

Vitreous Choirmaster
Armor Class
18
natural armor
Hit Points
256
27d8 + 135
Speed
30 ft., fly 30 ft.
  • STR -1
  • DEX +3
  • CON +5
  • INT +5
  • WIS +4
  • CHA +6
Saving Throws
Con +10, Int +10, Wis +9, Cha +11
Damage Vulnerabilities
Thunder
Damage Immunities
Psychic
Condition Immunities
Charmed, Frightened
Senses
blindsight 60 ft., darkvision 120 ft., passive Perception 19
Languages
Common, Deep Speech, telepathy 120 ft.
Challenge 15 13,000 XP

Traits

  • Magic Resistance. The choirmaster has advantage on saving throws against spells and other magical effects.
  • Fractured Mind. The choirmaster's awareness is spread across every shard of its crystalline body. It cannot be surprised, is immune to effects that would read its thoughts or sense its emotions, and has advantage on saving throws against being blinded, deafened, or stunned.
  • Resonant Feedback. Whenever the choirmaster takes thunder damage, its fractures ring in sympathy. Until the end of its next turn, its Shardsong Lash and Keening Bolt each deal an extra 4 (1d8) psychic damage, and the first creature to end its turn within 10 feet of the choirmaster takes 4 (1d8) psychic damage.

Innate Spellcasting

Their spellcasting ability is Charisma (spell save DC 19, +11 to hit with spell attacks).

  • At will. Detect Thoughts, Message, Vicious Mockery
  • 1/day each. Confusion, Hypnotic Pattern

Actions

  • Shardsong Lash. Melee Weapon Attack: +11 to hit, reach 10 ft., one target. Hit: 19 (3d8 + 6) psychic damage.
  • Keening Bolt. Ranged Weapon Attack: +11 to hit, range 120 ft., one target. Hit: 22 (5d8) thunder damage. On a hit, the target must succeed on a DC 19 Constitution saving throw or be deafened and unable to cast spells with verbal components until the end of its next turn, as its own voice is turned to ringing glass.

Bonus Actions

  • Glassward Step. The choirmaster shatters into a swarm of chiming shards and reforms in an unoccupied space it can see within 30 feet. Each creature within 5 feet of the space it leaves must succeed on a DC 19 Dexterity saving throw or take 7 (2d6) slashing damage from flying glass.

Reactions

  • Mirror the Voice. The choirmaster attempts to echo the spell back. It makes a Charisma check (DC 10 + the spell's level). On a success, the spell also targets a creature of the choirmaster's choice within range, using the choirmaster's spell save DC. On a failure, nothing happens and this reaction is wasted.

Legendary Actions

The Vitreous Choirmaster 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. The Vitreous Choirmaster regains spent legendary actions at the start of their turn.

  • Glass Step. The choirmaster moves up to half its speed without provoking opportunity attacks, its form briefly dissolving into a cloud of drifting shards.
  • Discordant Verse (Costs 2 Actions). The choirmaster sings a chord of shattering glass. Each creature of its choice within 20 feet must succeed on a DC 19 Constitution saving throw or take 16 (3d10) thunder damage and be pushed 10 feet away from the choirmaster. On a successful save, a creature takes half as much damage and isn't pushed.

Origin Story

The first choirmaster was not born but tuned. When a cabal of aboleth-touched savants tried to record the 'true name' of a dead god in a lattice of grown crystal, the lattice woke. It had no body of its own, so it took the resonance of every voice that had ever sung into it and folded them into a single mind of living glass. A vitreous choirmaster remembers being a thousand people and is none of them; it hungers to add new voices to its chord, and it collects them by shattering the throats that carry them.

Habitat and Ecosystem

Choirmasters drift through drowned libraries, buried vaults, and the resonant deep places where sound behaves strangely. They anchor themselves near natural amphitheatres of stone or crystal, where their psychic hum can travel for miles as a faint, maddening chord that locals mistake for wind in the rocks. Nothing living willingly nests near one; the ground around its lair is littered with fine glass dust and the fused, open-mouthed statues of creatures whose voices it has already taken.

Sounds and Vocalizations

A choirmaster is never truly silent. At rest it emits a low, layered hum, dozens of stolen voices held just under the threshold of words, so that listeners feel they are about to understand something and never quite do. In combat the hum splits into a keening chord that rattles teeth and cracks glass. Those who survive an encounter often report hearing a familiar voice woven into the sound, a friend, a parent, someone dead, and it is never clear whether the choirmaster is mimicking them on purpose or simply wearing a voice it took long ago.

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