Vallus the Dreadwrought

Building an Empire. If a humanoid is killed by Vallus and is cursed by Vallus, the humanoid cannot be revived by the Revivify spell, and must be buried and upon the sun setting after a Long Rest rise as a Vampire Spawn under Vallus's control. 

Legendary Resistance (4/Day, or 5/Day in Lair). If Vallus fails a saving throw, he can choose to succeed instead.

Regeneration. If Vallus has regained Hit Points from his Bite or Sanguine Drain abilities, he can regain 20 Hit Points at the start of his turn as long as he has at least 1 Hit Point. If he is in sunlight or has taken Radiant damage, he only regains 10 Hit Points.

Spider Climb. Vallus can climb on any surface without needing to make an ability check or use his hands.

Vampire of Dread. Vallus is the second vampire created behind only Kas. His vampirism is differs from other vampires. If Vallus dies his body disintegrates to ash and reforms in Tovag with all his Hit Points after 1d100 days. To truly kill Vallus you must stake him in the heart with a stake made from wood in Oerth and leave him in the sun.

Vampire Weakness. Vallus has these weaknesses:

Stake to the Heart. If a weapon that deals Piercing scores a Critical Hit while he has 100 Hit Points or fewer, he must succeed on a DC 20 Constitution saving throw (cannot use Legendary Resistance to succeed) or he has the Paralyzed condition until the weapon is removed.
Sunlight. Vallus takes 20 Radiant damage if he starts its turn in sunlight. While in sunlight, he has Disadvantage on attack rolls and ability checks.

Multiattack. Vallus makes three attacks, using Nightreaper or Ray of Dread in any combination. Vallus can exchange one attack for (A) a use of his Dread Reaping if available or (B) his Bite Attack. Vallus can cast a spell using Spellcasting in exchange for two attacks.

Bite. Melee Attack Roll: +13, reach 5 ft. Hit: 9 (1d4 + 7) Piercing damage plus 16 (3d10) Necrotic damage. The target’s Hit Point Maximum decreases by an amount equal to the Necrotic damage taken, and Vallus regains Hit Points equal to that amount. Constitution Saving Throw: DC 22, Failure: The target is Cursed by Valus and gains 1 level of Exhaustion. A creature affected by this ability makes a saving throw at the end of each of its turns. On a failed save, its level of Exhaustion increases by 1. On a successful save, its level of Exhaustion is reduced by 1. These saving throws are not affected by Exhaustion levels. 

Nightreaper. Melee Attack Roll: +13, reach 5 ft. Hit: 12 (1d10 + 7) Slashing damage plus 14 (4d6) Necrotic damage. If the target is not a Construct or Undead, they have the Poisoned condition until the end of their next turn.

Ray of Dread. Ranged Attack Roll: +13, range 120 ft. Hit: 26 (3d12 + 7) Psychic damage, and the target is Frightened and while Frightened in this way the targets movement speed is reduced to 0 and it cannot take a Reaction until the start Vallus’s next turn. 

Dread Reaping (Recharge 5-6). Wisdom Saving Throw: DC 22. Each creature of Valus’s choice within a 30-foot Emanation centered on him whenever the Emanation enters a creature’s space and whenever a creature enters the Emanation or ends its turn there. Failure: 32 (5d12) Psychic damage and affected creatures are Frightened until the start of their next turn. While Frightened in this way, the creatures have Disadvantage on saving throws forced by him. Success: Half damage only. Failure or Success: Valus’s Emanation is Magical Darkness that lasts until the start of his next turn, and a creature can only be forced to make the save once per round.

Spellcasting. Valus casts one of the following spells, requiring no Material components and using Charisma as his spellcasting ability (DC 22): 

At Will: Darkness (No Concentration), Detect Magic, Minor Illusion

2/Day Each: Dispel Magic, Doomtide (level 5 version), Hold Monster (level 6 version)

1/Day Each: Finger of Death, Harm, Power Word Pain

Sanguine Drain. Constitution Saving Throw: DC 22, one creature Vallus can see within 30 feet that isn’t a Construct or an Undead. Failure: 22 (4d10) Necrotic damage. The target’s Hit Point Maximum decreases by an amount equal to the damage taken, and Vallus regains Hit Points equal to that amount The target is also is cursed by Vallus, and is Drained until the end of their next turn. While Drained the target must subtract 1d8 from all D20 Tests and any saving throw DC.

Shadow Step. While in Dim-Light or Darkness Vallus can teleport up to 60 ft. to an unoccupied space that is in Dim-Light or Darkness.

Bait and Counter. Trigger: Creature makes a melee attack on Vallus. Response: Vallus adds 6 to his Armor Class, potentially causing the attack to miss. If the attack misses, Vallus pulls the attacker in to use his Bite attack on them. 

Protective Magic (3/Day). Vallus casts Counterspell or Shield in response to the spell’s trigger, using the same spellcasting ability as Spellcasting.

Legendary Action Uses: 3 (4 in Lair). Immediately after another creature’s turn, Vallus can expend a use to take one of the following actions. Vallus regains all expended uses at the start of each of its turns.

Beguile. Vallus casts Command (level 3 version) using his spellcasting ability requiring no spellcasting components. Vallus can’t take this action again until the start of his next turn.

Charm. Vallus casts Dominate Monster using his spellcasting ability requiring no spellcasting components. Vallus can choose to Concentrate on the spell as usual or not Concentrate on the spell and have it last until the start of his next turn. While a creature is Charmed in this way, it does not get to repeat its saving throw if Vallus deals damage to it and is a willing recipient of his Bite or Sanguine Drain attack. After the condition ends the affected creature does not know it was Charmed. Vallus can’t take this action again until the spell ends and the start of his next turn.

Feed. Vallus uses his Bite or Sanguine Drain attack. Vallus can’t take this action again until the start of his next turn.

Umbral Strike. Vallus can move up to half his Speed without provoking Opportunity Attacks and makes one Nightreaper or Ray of Dread attack.