Archdemon Grisel

Terrifying Presence. Any creature that starts its turn within 30 feet of Grisel must make a DC 20 Wisdom saving throw. On a failed save, the creature becomes frightened by Grisel for 1 minute or until it takes damage. On a successful save, the creature becomes immune to Grisel Terrifying Presence for 24 hours.

Taste the Fear. When a creature Grisel  can see within 60 feet of him is reduced to 0 hit points, he gains 25 temporary hit points.

Innate Spellcasting. Grisel’s spellcasting ability is Charisma (spell save DC 25). He can innately cast hellish rebuke (at 5th level) at will, requiring no material components.

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

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

Magic Weapons. Grisel weapon attacks are magical.

Multiattack. Grisel morphs weapons on both arms and then makes two attacks.

Morph. As a bonus action, Grisel is able to morph his arms into 4 different weapons. He always has two different weapons morphed:

• Claw. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 15 (2d6 + 8) slashing damage. The target must succeed on a DC 18 WIS save or be frightened of Grisel. The creature repeats the save at the end of its turn or when it takes damage.
• Scythe. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 17 (2d8 + 8) slashing damage. This attack reduces the targets max HP equal to 1/2 damage dealt.
• Hammer. Melee Weapon Attack: +10 to hit, reach 10 ft., one target. Hit: 19 (2d10+ 8) bludgeoning damage. This attack has advantage on creatures wearing medium or heavy armor.
• Harpoon. Melee Weapon Attack: +10 to hit, reach 60 ft., one target. Hit: 21 (3d8 + 8) piercing damage, and the target is grappled (escape DC 18) if it is a Large or smaller creature. The creature may then be pulled back to Grisel as a bonus action.
  
  

Grisel 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. Grisel regains spent legendary actions at the start of his turn.

Fear the Reaper. Each creature within 60 feet of Grisel that is frightened by him must use its reaction to cower in fear. While doing so, the creature is restrained and all attacks made against it gain advantage.

Attack (Costs 2 Actions). Grisel attacks with a morphed weapon. He is able to use Morph prior to the attack.

Nightmare Poison(Costs 3 Actions). Grisel attacks a target within 10 ft. of him. The target must succeed on a DC 20 Constitution saving throw or be poisoned for 1 minute. While poisoned in this way, the creature can’t maintain concentration on a spell or any other effect that requires concentration. The poisoned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.