Ancient Vampire Warlock of Orcus

Shapechanger. If the vampire isn't in sunlight or running water, it can use its action to polymorph into a Tiny bat, giant bat a Medium cloud of mist, or back into its true form.

While in bat form, the vampire can't speak, its walking speed is 5 feet, and it has a flying speed of 30 feet. The walking speed in giant bat form equals 10 feet and the flying speed 60 feet. Its statistics, other than its size and speed, are unchanged. Anything it is wearing transforms with it, but nothing it is carrying does. It reverts to its true form if it dies.

While in mist form, the vampire can't take any actions, speak, or manipulate objects. It is weightless, has a flying speed of 20 feet, can hover, and can enter a hostile creature's space and stop there. In addition, if air can pass through a space, the mist can do so without squeezing, and it can’t pass through water. It has advantage on Strength, Dexterity, and Constitution saving throws, and it is immune to all nonmagical damage, except the damage it takes from sunlight.

Legendary Resistance (5/Day). If the vampire fails a saving throw, it can choose to succeed instead.

Misty Escape. When it drops to 0 hit points outside its resting place, the vampire transforms into a cloud of mist (as in the Shapechanger trait) instead of falling unconscious, provided that it isn't in sunlight or running water. If it can't transform, it is destroyed.

While it has 0 hit points in mist form, it can't revert to its vampire form, and it must reach its resting place within 2 hours or be destroyed. Once in its resting place, it reverts to its vampire form. It is then paralyzed until it regains at least 1 hit point. After spending 1 hour in its resting place with 0 hit points, it regains 1 hit point.

Regeneration. The vampire regains 30 hit points at the start of its turn if it has at least 1 hit point and isn't in sunlight or running water. If the vampire takes radiant damage or damage from holy water, this trait doesn't function at the start of the vampire's next turn.

Spider Climb. The vampire can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.

Unholy Persistence. The vampire is immune against effects that turn undead.

Vampire Weaknesses. The vampire has the following flaws:

Forbiddance. The vampire can't enter a residence without an invitation from one of the occupants.

Harmed by Running Water. The vampire takes 20 acid damage if it ends its turn in running water.

Stake to the Heart. If a piercing weapon made of wood is driven into the vampire's heart while the vampire is incapacitated in its resting place, the vampire is paralyzed until the stake is removed.

Sunlight Sensitivity. While in sunlight, the vampire has disadvantage on attack rolls, as well as on Wisdom (Perception) checks that rely on sight.

Warlock Abilitys

Pact of the Blade. The vampire can summon it's pact weapon as an action. This weapon can be a meele weapon, shortbow, longbow, light crossbow, or heavy crossbow.

Dark One’s Blessing. When the vampire reduces a hostile creature to 0 hit points, it gains 17 temporary hit points.

Dark One’s Own Luck (1/rest). When the vampire makes an ability check or a saving throw, it can use this feature to add a d10 to it's roll.

Fiendish Resilience. The vampire can choose one damage type when it finishs a short or long rest. The vampire gains resistance to that damage type until it chooses a different one with this feature.

Hurl Through Hell (1/long rest). When the vampire hits a creature with an attack, it can use this feature to instantly transport the target through the lower planes. The creature disappears and hurtles through a nightmare landscape.

At the end of the vampire's next turn, the target returns to the space it previously occupied, or the nearest unoccupied space. If the target is not a fiend, it takes 10d10 psychic damage as it reels from its horrific experience.

Eldritch Master (1/long rest). The vampire can spend 1 minute entreating it's patron for aid to regain all it's expended spell slots from it's Pact Magic feature.

Invocations

Eldritch Smite. Onnce per turn, when the vampire hits a creature with it's pact weapon, it can expad a worlock spell slot to deal extra 1d8 force damage to the target, plus another 1d8 per level of the spell slot, and the vampire can knock the target prone if it is huge or smaller.

Mire the Mind. The vampire can cast slow once using a warlock spell slot. It can’t do so again until it finishs a long rest.

Shroud of Shadow. The vampire can cast invisibility at will, without expending a spell slot.

Agonizing Blast. When you cast eldritch blast, add your Charisma modifier to the damage it deals on a hit. (included)

Repelling Blast. When you hit a creature with eldritch blast, you can push the creature up to 10 feet away from you in a straight line. (included)

Spellcasting

Spellcasting. The vampire is a 20th-level spellcaster. Its spellcasting ability is Charisma (spell save DC 22, +14 to hit with spell attacks). It regains its expended spell slots when it finishes a short or long rest. It knows the following warlock spells:

Cantrips (at will): chill touch, mage hand, minor illusion, disguise self, alter self, eldritch blast(4 beams, +6 to damage rolls for each beam, can push the target up to 10 feet away in a straight line), invisibility

1st-5th level (4 5th-level slots):
command, burning hands, hex, darkness

blindness/deafness, scorching ray, hold person

fireball, stinking cloud, counterspell, major image, summon lesser demons, fly

fire shield, wall of fire, banishment, sickening radiance, shadow of moil, summon greater demon

flame strike, hallow, scrying, enervation

Mystic Arcanum (6th level): tasha's otherworldly guise

Mystic Arcanum (7th level): plane shift

Mystic Arcanum (8th level): glibness

Mystic Arcanum (9th level): foresight

Undying Soul (1/rest). If the Vampire is reduced to 0 hit points, it immediatly makes a DC 10 Constetution saving throw. If it succseeds, it is instead reduced to 1 hit point.

Aura of Death. The Vampire emanates a deathly aura that extends 30 feet in every direction from its space while it isn't incapacitated. The aura is blocked by total cover. While in the aura, the creature and any friendly undead are immune to the frightened condition and have resistance to radiant damage. Enemies suffer disadvantage on death saving throws while in the aura.

 Enhanced Attacks. The vampire's attacks are treated as magical for the purpose of overcoming resistance and immunity to nonmagical damage. The damage dice are doubled for any weapon and the vampire deals extra 14 (4d6) necrotic damage (included).

Multiattack. (Vampire Form Only). The vampire makes three attacks, only one of which can be a bite attack.

Flame Tounge. (Vampire Form Only). Melee Weapon Attack: +13 to hit, reach 5 ft., one creature. Hit: 19 (4d6 + 5) bludgeoning damage, 14 (4d6) fire damage and 20 (4d6 + 6) necrotic damage.

Vaporal Sword. (Vampire Form Only). Melee Weapon Attack: +16 to hit, reach 5 ft., one creature. Hit: 22 (4d6 + 8) bludgeoning damage, 20 (4d6 + 6) necrotic damage.
If the target has at least one head and the Vampire rolled a 20 on the attack roll, the target is decapitated and dies if it can't survive without that head. A target is immune to this effect if it takes none of the damage, has legendary actions, or is Huge or larger. Such a creature takes an extra 6d8 slashing damage from the hit.

Unarmed Strike (Vampire Form Only). Melee Weapon Attack: +13 to hit, reach 5 ft., one creature. Hit: 20 (3d8 + 6) bludgeoning damage and 14 (4d6) necrotic damage. Instead of dealing damage, the vampire can grapple the target (escape DC 22).

Bite. (Bat or Vampire Form Only). Melee Weapon Attack: +13 to hit, reach 5 ft., one willing creature, or a creature that is grappled by the vampire, incapacitated, or restrained. Hit: 19 (4d6 + 5) piercing damage plus 42 (12d6) necrotic damage. The target's hit point maximum is reduced by an amount equal to the necrotic damage taken, and the vampire regains hit points equal to that amount. The reduction lasts until the target finishes a long rest. The target dies if this effect reduces its hit point maximum to 0. A humanoid slain in this way and then buried in the ground rises the following night as a vampire spawn under the vampire's control.

Greater Charm. The vampire targets one humanoid it can see within 30 feet of it. If the target can see the vampire, the target must succeed on a DC 22 Wisdom saving throw against this magic or be charmed by the vampire. The charmed target regards the vampire as a trusted friend to be heeded and protected. Although the target isn't under the vampire's control, it takes the vampire's requests or actions in the most favorable way it can, and it is a willing target for the vampire's bite attack.

Each time the vampire or the vampire's companions do anything harmful to the target, it can repeat the saving throw, ending the effect on itself on a success. Otherwise, the effect lasts 24 hours or until the vampire is destroyed, is on a different plane of existence than the target, or takes a bonus action to end the effect.
If the vampire charms a target 7 days in a row and the target couldn't pass the saving throw at least once, the target is charmed permanantly.

Children of the Night (1/Day). The vampire magically calls 6d6 swarms of bats or rats (swarm of bats, swarm of rats), provided that the sun isn't up. While outdoors, the vampire can call 4d8 dire wolves (dire wolf) instead. The called creatures arrive in 1d4 rounds, acting as allies of the vampire and obeying its spoken commands. The beasts remain for 1 hour, until the vampire dies, or until the vampire dismisses them as a bonus action.

The vampire can take 3 legendary actions (5 legendary actions if more than 5 PCs), 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. The vampire regains spent legendary actions at the start of its turn.

Move. The vampire moves up to its speed without provoking opportunity attacks or it teleports up to 120 feet to an unoccupied space that it can see.

Meele Attack. The vampire makes one unarmed strike or attacks with his sword.

Casting a Cantrip. The vampire can cast a cantrip.

Bite.(Costs 2 Actions). The vampire makes one bite attack.

Casting a Spell. (Costs 2 Actions) The vampire can cast a spell.

Greater Charm (Costs 3 Actions). The vampire uses it's Greater Charm.