Nhaal-Uthys, the Trench That Dreams

Gargantuan aberration, chaotic neutral · CR 27

by Deepsounding

Nhaal-Uthys, the Trench That Dreams
Armor Class
22
natural armor
Hit Points
656
32d20 + 320
Speed
20 ft., fly 40 ft., swim 120 ft.
  • STR +10
  • DEX +2
  • CON +10
  • INT +8
  • WIS +7
  • CHA +8
Saving Throws
Str +18, Con +18, Int +16, Wis +15
Skills
Arcana +16, History +16, Insight +15, Perception +15
Damage Resistances
Bludgeoning (nonmagical), Fire, Lightning, Piercing (nonmagical), Slashing (nonmagical), Thunder
Damage Immunities
Cold, Poison, Psychic
Condition Immunities
Blinded, Charmed, Deafened, Frightened, Paralyzed, Petrified, Poisoned, Prone, Stunned
Senses
darkvision 120 ft., tremorsense 120 ft., truesight 120 ft., passive Perception 25
Languages
understands Deep Speech, Primordial, Aquan but can't speak, telepathy 120 ft.
Challenge 27 105,000 XP

Traits

  • Amphibious. Nhaal-Uthys can breathe air and water.
  • Legendary Resistance (3/Day). If Nhaal-Uthys fails a saving throw, it can choose to succeed instead.
  • Magic Resistance. Nhaal-Uthys has advantage on saving throws against spells and other magical effects.
  • Dreaming Depth. Nhaal-Uthys is never fully awake. Any creature that finishes a long rest within 20 miles of it must succeed on a DC 26 Wisdom saving throw or gain no benefit from that rest, having spent the night inside a fragment of the trench's dream. On a failed save by 5 or more, the creature also learns one true thing it did not want to know.
  • Crushing Presence. The water around Nhaal-Uthys carries its weight. A creature that starts its turn within 60 feet of it takes 22 (4d10) bludgeoning damage and has its speed halved until the start of its next turn unless it is immune to being grappled.

Actions

  • Multiattack. Nhaal-Uthys makes one Sounding Cry attack and three Tendril attacks, or it makes four Tendril attacks.
  • Tendril. Melee Weapon Attack: +19 to hit, reach 40 ft., one target. Hit: 43 (6d10 + 10) bludgeoning damage. The target is grappled (escape DC 27) if it is a Huge or smaller creature, and it is restrained until the grapple ends.
  • Sounding Cry (Recharge 5-6). Nhaal-Uthys sounds a single note that the water carries for a hundred miles. Each creature in the area must make a DC 26 Constitution saving throw, taking 72 (16d8) thunder damage on a failed save, or half as much damage on a successful one. On a failed save, a creature is also deafened and stunned for 1 minute. Each creature within 120 feet of it must make the saving throw.
  • Draw Down. Nhaal-Uthys pulls one creature it is grappling into the trench. The creature descends 200 feet, takes 44 (8d10) cold damage from the pressure, and must succeed on a DC 26 Constitution saving throw or fall unconscious for 1 minute. A creature that begins its turn below this depth repeats the damage.

Bonus Actions

  • Sink. Nhaal-Uthys descends up to 60 feet without provoking opportunity attacks. Any creature it is grappling descends with it.

Reactions

  • The Trench Answers. Trigger: A creature within 120 feet casts a spell of 5th level or higher. Nhaal-Uthys dreams the spell differently. The caster must succeed on a DC 26 Charisma saving throw or the spell fails and its slot is expended, and the caster takes 27 (6d8) psychic damage.

Legendary Actions

Nhaal-Uthys, the Trench That Dreams 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. Nhaal-Uthys regains spent legendary actions at the start of their turn.

  • Tendril. Melee Weapon Attack: +19 to hit, reach 40 ft., one target. Hit: 43 (6d10 + 10) bludgeoning damage. The target is grappled (escape DC 27) if it is a Huge or smaller creature, and it is restrained until the grapple ends.
  • Undertow (Costs 2 Actions). Nhaal-Uthys drags the water. Each creature within 60 feet must succeed on a DC 26 Strength saving throw or be pulled up to 40 feet toward it and knocked prone.
  • A Dream of Drowning (Costs 3 Actions). One creature Nhaal-Uthys can see within 120 feet dreams, briefly, that it has always been underwater. It must succeed on a DC 26 Wisdom saving throw or begin suffocating as though it had no air for 1 minute, repeating the save at the end of each of its turns.

Lair Actions

  • Lair Action 1. The trench exhales. A column of freezing water 30 feet wide erupts from the seabed at a point Nhaal-Uthys can see within 120 feet; each creature in it must succeed on a DC 26 Constitution saving throw or take 27 (6d8) cold damage and be pushed 20 feet upward.
  • Lair Action 2. The pressure changes without warning. Each creature within 120 feet of Nhaal-Uthys must succeed on a DC 26 Constitution saving throw or be deafened and have disadvantage on Wisdom (Perception) checks until initiative count 20 on the following round.

Regional Effects

  • Regional Effect 1. Within 20 miles of the trench, the sea does not reflect the sky. Navigators lose the horizon at dusk and cannot fix a position by star or sun until they leave the region. The effect extends 1 miles from the lair.
  • Regional Effect 2. Fish within 20 miles of the trench swim in slow, deliberate patterns that observers describe as writing. Any creature that watches them for 10 minutes must succeed on a DC 20 Wisdom saving throw or be compelled to travel toward the trench for the next hour. The effect extends 1 miles from the lair.

Origin Story

The Kethran cartographers who first sounded the Nhaal Deep recorded its depth as "no bottom found at 4,000 fathoms" and moved on. They did not record that the line came back up warm, or that every man on the sounding crew dreamed the same dream that night: a slow grey shape, a long way down, turning over in its sleep. Nhaal-Uthys has never surfaced, has never been seen entire, and is known chiefly by the things that stop happening near it — the currents that go still, the whales that stop singing, the century in which no ship out of Kethra ever reported a storm. Scholars disagree on whether it is a creature that dreams or a dream that has acquired a body. It has not been asked.

Habitat and Ecosystem

Nhaal-Uthys occupies the full column of the trench, from the cold floor to about 3,000 feet below the surface, and it does not leave. Nothing else large lives there, but the trench is not empty: the walls are thick with pale, slow-growing life that appears to feed on nothing at all, and there is a resident population of blind cephalopods that behave, at a distance, like a nervous system. Whalers working the shelf above the trench report exceptional catches and a superstition against sounding the depths, and both are correct — the shelf is rich precisely because nothing that swims will go down.

Behavior Patterns

Nhaal-Uthys is not hostile, and this is the most dangerous thing about it. It has no territorial response, no hunting behaviour, and no apparent interest in anything that enters the trench; creatures that descend are usually killed by pressure, cold and the thing's sheer incidental motion long before it registers them. What it does have is a dream, and the dream is enormous and slightly porous, and anyone who sleeps within twenty miles is sleeping partly inside it. Expeditions that reach the trench floor rarely die fighting. They die because, some weeks later, back on land, they walk into the sea. A DM running Nhaal-Uthys should treat combat as a failure state for the party rather than the encounter's purpose: it is a thing to be survived, understood, or left alone.

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