Legendary Resistance (3/Day). If the emperor fails a saving throw, he can choose to succeed instead.
Sunlight Sensitivity. While in direct sunlight, the emperor has disadvantage on attack rolls and Wisdom (Perception) checks that rely on sight.
Turn Resistance. The emperor has advantage on saving throws against effects that turn undead.
Multiattack. The emperor makes one bite attack and two claw attacks. He can make one attack with its scepter in place of a claw attack.
Bite. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 13 (2d8+4) piercing damage, and a creature must make a successful DC 18 Constitution saving throw or contract darakhul fever.
Claw. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 11 (2d6+4) slashing damage, and a creature must make a successful DC 18 Constitution saving throw or be paralyzed for 1 minute. A paralyzed creature repeats the saving throw at the ends of its turns, ending the effect on itself on a success.
Scepter. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 9 (1d10+4) bludgeoning damage plus 17 (5d6) necrotic damage.
Emperor of the Ghouls can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. Emperor of the Ghouls regains spent legendary actions at the start of its turn.
Attack. The emperor makes one claw or bite attack.
Cantrip. The emperor casts a cantrip.
Font of Power (3 actions). Roll 1d8. The emperor regains a spell slot of that level or lower.
Turning Defiance. The iron ghoul and any ghouls within 30 feet of it have advantage on saving throws against effects that turn undead.
Multiattack. The iron ghoul makes one bite attack and one claw attack, or three glaive attacks.
Bite. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 17 (3d8+4) piercing damage. If the target is a creature other than an elf or undead, it must succeed on a DC 13 Constitution saving throw or be paralyzed for 1 minute. The target repeats the saving throw at the end of each of its turns, ending the effect on itself on a success. If the target is humanoid, it must succeed on a separate DC 13 Constitution saving throw or contract darakhul fever.
Claws. Melee Weapon Attack: +7 to hit, reach 5 ft., one target. Hit: 18 (4d6+4) slashing damage. If the target is a creature other than an elf or undead, it must succeed on a DC 13 Constitution saving throw or be paralyzed for 1 minute. The target repeats the saving throw at the end of each of its turns, ending the effect on itself on a success. If the target is humanoid, it must succeed on a separate DC 13 Constitution saving throw or contract darakhul fever.
Glaive. Melee Weapon Attack: +7 to hit, reach 10 ft., one target. Hit: 20 (1d10+4) slashing damage.
Heavy Bone Crossbow. Ranged Weapon Attack: +6 to hit, range 100/400, one target. Hit: 8 (1d10+3) piercing damage.
Amorphous. The bonepowder ghoul can move through a space as narrow as 1 inch wide without squeezing.
Coalesce. Whenever a bonepowder ghoul drains life force from victims with Gravedust, it can use that energy transform its shape into a more solid form and maintain it. The new form is Small and semi-transparent but roughly the shape of a normal ghoul. In this form, the ghoul isn't amorphous and can't form a whirlwind, but it can speak normally and manipulate objects. The altered form lasts for 1 minute for every point of necrotic damage it delivered against living foes.
Turning Defiance. The bonepowder ghoul and any other ghouls within 30 feet of it have advantage on saving throws against effects that turn undead.
Bite. Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 18 (3d8+5) plus 1d4 Strength damage, and the target must succeed on a DC 17 Constitution saving throw or be paralyzed for 1d4+1rounds. If the target creature is humanoid, it must succeed on a second DC 19 Constitution saving throw or contract darakhul fever.
Gravedust. A bonepowder ghoul can project a 40 foot cone of grave dust. All targets within the area must make a DC 19 Dexterity saving throw to avoid taking 4d8 necrotic damage, and must make a second DC 17 Constitution saving throw to avoid being infected with darakhul fever.
Whirlwind (Recharge 5—6). A bonepowder ghoul can generate a whirlwind of bones and teeth. All creatures within a 20-foot cube take 66 (12d10) slashing damage and are drained of 1d6 Strength, a successful DC 17 Dexterity saving throw reduces damage to half and negates the Strength loss. The whirlwind dissipates after one round.
Innate Spellcasting. The bonepowder ghoul's innate spellcasting ability is Charisma (spell save DC 18, +10 to hit with spell attacks). It can innately cast the following spells, requiring no material components:
At will: chill touch, darkness, dispel magic, ray of enfeeblement
3/day: blindness/deafness, circle of death (7th level, 10d6)
1/day: finger of death