Azrakaus

Regeneration. Azrakaus regains 30 hit points at the start of each of his turns. 

Glaive of Azrakaus. The glaive is a +15 artifact that has 10 charges, and any of its properties that require a saving throw have a save DC of 24. While holding it, Azrakaus can use an action to cast animate dead, blight, or speak with dead. Alternatively, he can expend 1 or more of the glaive’s charges to cast one of the following spells from it: circle of death (1 charge), finger of death (1 charge), or power word kill (3 charges). The wand regains 1d6 + 4 charges daily at dawn.

While holding the glaive, Azrakaus can use an action to conjure undead creatures whose combined average hit points don’t exceed 500 or 15 creatures. These undead magically rise up from the ground or otherwise form in unoccupied spaces within 300 feet of Azrakaus and obey his commands until they are destroyed or until he dismisses them as an action. Once this property of the glaive is used, the property can’t be used again until the next dawn.

Innate Spellcasting. Azrakaus’s spellcasting ability is Charisma (spell save DC 24, +15 to hit with spell attacks). He can innately cast the following spells, requiring no material components:

At will: chill touch (17th level), detect magic

3/day each: create undead, dispel magic

1/day: time stop

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

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

Magic Weapons. Azrakaus’s weapon attacks are magical.

Master of Undeath. When Azrakaus casts animate dead or create undead, he chooses the level at which the spell is cast, and the creatures created by the spells remain under his control indefinitely. Additionally, he can cast create undead even when it isn’t night.

Aura of Enfeeblement. Black beams of negative energy surround Orcus in a 20-foot radius centered on him. Each creature in this area must make a DC 24 Dexterity saving throw at the start of its turn. On a failure, the target has disadvantage on strength saving throws, strength based attacks, and skill checks based on strength. Creatures affected may make another save at the end of their turn.

Multiattack. Orcus makes two Glaive of Azrakaus or Slam attacks.

Slam. Melee Weapon Attack: +18 to hit, reach 10 ft., one target. Hit:  31 (6d8+15) bludgeoning damage. 

Glaive of Azrakaus. Melee Weapon Attack: +18 to hit, reach 10 ft., one target. Hit: 21 (3d8 + 15) slashing damage plus 24 (4d12) necrotic damage.

Tail. Melee Weapon Attack: +16 to hit, reach 10 ft., one target. Hit: 21 (3d8 + 15) piercing damage plus 9 (2d8) poison damage.

Grasp of Undeath (recharge 6). Melee Weapon Attack: +21 to hit, reach 10 ft., one target. Hit: 33 (6d10) necrotic damage and the target must make a DC 24 Strength saving throw. On a failed save the target's maximum hit points are reduced by that amount, and Azrakus gains those hit points as temporary hit points. 

Necrotic Bolt (recharge 5-6). Azrakaus creates a bolt of necrotic energy that arcs towards a target he can see within 150 feet. Four bolts then leap from the initial target and hit up to four targets within 30 feet of the initial target. Each target must make a DC 24 Constitution saving throw or take 30 (6d10) points of necrotic damage or half as much on a successful save. 

Frightful Presence. Each creature of the Azrakaus's choice that is within 120 feet of him and aware of him must succeed on a DC 24 Wisdom saving throw or become frightened for 1 minute. A creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success. If a creature fails 3 times then it much roll on the Madness of Azrakaus chart.

Necrotic Recharge. When Azrakaus is subject to an attack or effect that deals necrotic damage, instead of taking damage he regains hit points equal to the damage dealt. 

Tail Attack. Azrakaus makes a tail attack when a creature moves into or starts it's turn within reach of Azrakaus's tail. 

Azrakaus can take 5 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. Orcus regains spent legendary actions at the start of his turn.

Tail. Azrakaus makes one tail attack.

Glaive/Slam. Azrakaus makes 2 attacks with the Glaive of Azrakaus or his fists. 

A Taste of Undeath. Azrakaus casts chill touch (17th level).

Teleport. Azrakaus magically teleports along with anything he is wearing or carrying to a place within 240 feet of him. 

Creeping Death (Costs 2 Actions). Azrakaus chooses a point on the ground that he can see within 100 feet of him. A cylinder of swirling necrotic energy 60 feet tall and with a 20-foot radius rises from that point and lasts until the end of Azrakaus’s next turn. Creatures in that area must make a DC 24 Con save, or until the end their turn there are vulnerable to necrotic damage until the end of their next turn. Creatures move through the energy, or start/end their turn in the energy must make the same save.

Charnel Wind (Costs 3 Actions). A putrid, carrion wind erupts from Azrakaus in a 30 foot radius centered on him. All non-undead creatures within this area must succeed on a DC 24 Constitution saving throw against disease or be poisoned until the end of Azrakaus's next turn. While poisoned in this way, a creature moves at half speed, can take either an action or a bonus action on its turn, not both, and cannot take reactions. 

Devouring Darkness (2 Actions). Azrakaus chooses a point that it can see within 100 feet of it. A cloud of darkness erupts from that point and lasts for a minute. The area is heavily obscured and each creature in the area must make a DC 24 Constitution saving throw taking 28 (8d6) necrotic damage or half as much on a successful one. Creatures slain by the devouring darkness rise as ghouls under the control of Azrakaus in 1d4 turns.