The Thousand Voices, Supreme Soul Vortex

At the start of each of the Thousand Voices's turns, each creature within 10 feet of the Thousand Voices take 5 (1d10) cold damage.

The Ten Thousand Voices can occupy another creature's space and vice versa. The Thousand Voices can move through other creatures and objects as if they were difficult terrain. It takes 5 (1d10) force damage if it ends its turn inside an object.

If the Thousand Voices fails a saving throw, it can choose to succeed instead.

3/DAY

The Thousand Voices is immune to spells of 6th level or lower unless it wishes to be affected. It ahs advantage on saving throws against all other spells and magical effects.

The Thousand Voices's AC includes its Intelligence modifier. In addition, when the Thousand Voices takes damage other than radiant damage while concentrating on a spell, it automatically succeeds on the Constitution saving throw made the maintain the concentration.

When the Thousand Voices is subjected to necrotic damage, it takes no damage and instead regains a number of hit points equal to the necrotic damage dealt.

At the start of each of the Thousand Voices's turns, it rolls a d4 to determine which list of spell is available to it until the start of its next turn. The Thousand Voices's innate spellcasting ability is Intelligence (spell save DC 24, +16 to hit with spell attacks). The Thousand Voices can innately cast the following spells as a 20th-level spellcaster, requiring no material components.

Remembered Spellcasting

The Thousand Voices is immune to the effects that turn undead.

The Thousand Voices can use its Terrifying Visage. It then uses its Cacophonous Shriek or casts two spells of 3rd level or lower.

Each non-undead creature within 60 feet of the Thousand Voices must make a DC 21 Constitution saving throw, with disadvantage if the target is within 5 feet of the Thousand Voices. A target takes 28 (8d6) necrotic damage and 28 (8d6) thunder damage on a failed save, or half as much damage on a successful one.

The Thousand Voices enters the space between the planes from the Material Plane, or vice versa. It can remain in the space between the planes for up to 1 minute, and when it returns to the Material Plane, it reappears in a space of its choice within 60 feet of the space it left. While it is in the space between the planes, it can't affect or be affected by anything on any other plane.

Each non-undead creature within 60 feet of the Ten Thousand Voices that can see it must succeed on a DC 20 Wisdom saving throw or become frightened for 1 minute. If the save fails by 5 or more, the target's speed is also reduces to 0 for the duration. A frightened target can repeat the save at the end of each of its turns, with disadvantage if the Thousand Voices is within line of sight, ending the effect on itself on a success. If a target's saving throw is successful or the effect ends for it, the target is immune to the Thousand Voices's Terrifying Visage for the next 24 hours.

The Thousand Voices can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at any time and only at the end of another creature's turn. The Thousand Voices regains spent legendary actions at the start of its turn.

3/TURN

The Thousand Voices uses its Extraplanar Shift.

The Thousand Voices casts a cantrip (1 action), a 3rd-level spell (2 actions), or a spell it can cast once per day (3 actions).

The Thousand Voices uses its Cacophonous Shriek

Each creature within 10 feet of the Thousand Voices must make a DC 20 Wisdom saving throw. On a failure, a target takes 14 (4d6) psychic damage, can't take reactions until the start of its next turn, and rolls a d4 to determine what it does during its next turn. On a 1 or 2, the target falls prone and then ends its turn. On a 3, the target takes no action or bonus action and uses all its movement to move in a randomly determined direction. On a 4, the target uses all of its movement to move within reach of a random creature, and then uses its action to make a melee weapon attack against that creature; if the target can't move within reach of another creature, it drops whatever it is holding and then end its turn.

Though many believe this space to be simply an unchartable portion of the astral plane, there simply is not enough information available either way. By all accounts, only those unfortunate enough to fall into the Space Between or invited in by a Soul Vortex can access the space, as planar teleportation has thus far failed on every occasion. It is described as a true void, where even astral starlight dares not venture.

On initiative count 20 (losing initiative ties), the Thousand Voices can take one of the following lair actions:

• The Thousand Voices magically summons 1d4 will-o'-wisps. A summoned will-o'-wisp appears in an unoccupied space within 60 feet of the Thousand Voices and acts as an ally of the Thousand Voices. It disappears if the Thousand Voices dies.

• The Thousand Voices casts the chill touch spell, targeting every creature of its choice within 120 feet of it. When it casts the spell in this way, it uses a spell attack bonus of +10, and deals 18 (4d8) damage on a hit.

• The Thousand Voices targets up to two creatures it can see within 60 feet of it, attempting to hurl them through the space between the planes. A target must succeed on a DC 15 Charisma saving throw or take 33 (6d10) force damage as it is forcibly shunted through this extradimensional space, disappearing with a faint popping noise. On initiative count 20 on the next round, the creature returns to the space it previously occupied, or the nearest unoccupied space.