Entropic Aura. Each creature that is not a construct or undead that ends its turn within 15 feet of Ygorl takes 14 (4d6) necrotic damage.

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

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

Magic Weapons. Ygorl's weapon attacks are magical.

Multiattack. Ygorl makes one scythe attack, one Entropic Touch attack, and one Chaos Spear attack.

Scythe. Melee Weapon Attack: +14 to hit, reach 10 ft., one creature. Hit: 18 (2d10 + 7) slashing damage plus 19 (3d12) necrotic damage. Any creature reduced to 0 hit points by this attack dies, with its body and everything it is wearing and carrying, except magic items, exploding into a cloud of ash. The creature can be restored to life only by means of a wish spell.

Entropic Touch. Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 20 (3d8 + 7) necrotic damage, and the target must succeed on a DC 22 Constitution saving throw or gain one level of exhaustion.

Chaos Spear. Ranged Spell Attack: +15 to hit, range 120 ft., one target. Hit: 21 (6d6) damage plus 9 (2d8) damage. Ygorl chooses one of the d8s. The number rolled on that die determines the attack’s damage type, as shown below.

1. Acid damage
2. Cold damage
3. Fire damage
4. Force damage
5. Lightning damage
6. Poison damage
7. Psychic damage
8. Thunder damage

If Ygorl rolls the same number on both d8s, the chaotic energy leaps from the target to a different creature of Ygorl's choice within 30 feet of the original target. Ygorl makes a new attack roll against the new target, and makes a new damage roll, which could cause the chaotic energy to leap again.

Circle of Entropy (Recharge 5–6). Ygorl creates a sphere of negative energy centered on a point it can see within 120 feet of it. Each creature that is not a construct or undead in a 60-foot-radius sphere centered on that point must make a DC 23 Constitution saving throw, taking 35 (10d6) necrotic damage on a failed save, or half as much damage on a successful one. A humanoid killed by this damage rises at the start of Ygorl's next turn as a zombie that is permanently under its command, following Ygorl's telepathic orders to the best of its ability.

Teleport. Ygorl teleports, along with any equipment it is wearing or carrying, up to 120 feet to an unoccupied space it can see.

Innate Spellcasting. Ygorl casts one of the following spells, requiring no material components and using Charisma as the spellcasting ability (spell save DC 23, +15 to hit with spell attacks).

At will: blink, darkness, detect magic, detect thoughts

3/day each: mental prison, phantasmal killer, power word pain, symbol (discord only) (as an action)

1/day each: power word kill, power word stun, summon aberration (slaad only) (at 9th-level), symbol (death only) (as an action), weird

Arcane Defense. When it is hit by an attack, Ygorl protects itself with an invisible barrier of magical force. Until the end of its next turn, Ygorl gains a +5 bonus to AC, including against the triggering attack.

Ygorl can take 3 legendary actions, choosing from the options below. It can take only one legendary action at a time and only at the end of another creature’s turn. Ygorl regains spent legendary actions at the start of its turn.

Scythe. Ygorl makes one attack with its scythe.

Chaos Magic. Ygorl uses Innate Spellcasting or Teleport.

Call the Void (Costs 2 Actions). Each creature that is not a construct or undead within 30 feet of Ygorl must make a DC 22 Constitution saving throw against the lord of entropy’s attempt to unmake life, taking 42 (12d6) necrotic damage on a failed save, or half as much damage on a successful one. Ygorl then regains a number of hit points equal to half the total damage taken by all affected creatures.