Shapechanger. If Dracula isn’t in sunlight or running water, he can use his action to polymorph into a Tiny bat or a Medium cloud of mist, or back into his true form.

While in bat form, his walking speed is 5 feet, and he has a flying speed of 60 feet. his statistics, other than his size and speed, are unchanged. Anything he is wearing transforms with him. He reverts to his true form if he dies.

While in mist form, Dracula can’t take any actions, speak, or manipulate objects. He 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. He has advantage on Strength, Dexterity, and Constitution saving throws, and it is immune to all nonmagical damage, except the damage he takes from sunlight.

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

Vampire Weaknesses. Dracula has the following flaws:

Stake to the Heart. If a piercing weapon made of wood is driven into Dracula's heart while he is incapacitated Dracula is instantly reduced to 0hp and destroyed.

Sunlight Hypersensitivity. Dracula takes 20 radiant damage when he starts his turn in sunlight. While in sunlight, he has disadvantage on attack rolls and ability checks.

Frightful Presence: Each creature of Dracula's choice that is within 120 feet of the dragon and aware of it must succeed on a DC 16 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 for itself on a success. If a creature's saving throw is successful or the effect ends for it, the creature is immune to Dracula's frightful presence for the next 24 hours.

Spellcasting. Dracula is a 20th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 17, +8 to hit with spell attacks). The vampire has the following spells prepared:

At Will: Animate Dead, Fog Cloud, Misty Step
Cantrips (at will): Chill Touch, Mage Hand, Minor Illusion, Toll the Dead
1st level (4 slots): Hellish Rebuke, Charm Person, Arms of Hadar, Burning Hands, Shield
2nd level (3 slots): Blindness/Deafness, Detect Thoughts, Invisibility, Darkness, Flock of Familiars
3rd level (3 slots): Dispel Magic, Counterspell, Fireball, Fear, Vampiric Touch, Enemies Abound
4th level (3 slots): Blight, Greater Invisibility, Spirit of Death, Summon Greater Demon, 
5th level (3 slots): Destructive Wave, Dominate Person, Far Step, Flame Strike, Immolation
6th level (2 slots): Summon Fiend, True Seeing
7th level (0 slots): Divine Word, Fire Storm
8th level (0 slots): Dark Star
9th level (0 slots): Meteor Swarm, Power Word: Kill, Demonic Megiddo*

*Demonic Megiddo can only be cast through mythic actions.

Multiattack. (Vampire Form Only). Dracula makes two melee attacks, only one of which can be a bite attack.

Unarmed Strike (Vampire Form Only). Melee Weapon Attack: +10 to hit, reach 5 ft., one creature. Hit: 21 (3d8 + 7); bludgeoning damage. As well as dealing damage, Dracula can throw the target 30 feet on a failed Strength save (DC 18), target takes 1d8 bludgeoning damage on colliding with anything.

Bite. (Bat or Vampire Form Only). Melee Weapon Attack: +6 to hit, reach 5 ft., one willing creature, or a creature that is grappled by the vampire, incapacitated, or restrained. Hit: 21 (3d8 + 7) piercing damage plus 12 (4d6) necrotic damage or half as much on successful DC14 Con Save. 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.

Charm. Dracula targets one humanoid he can see within 30 feet of him. If the target can see him, the target must succeed on a DC 17 Wisdom saving throw against this magic or be charmed by him. The charmed target regards Dracula as a trusted friend to be heeded and protected. Although the target isn’t under his control, it takes his requests or actions in the most favourable way it can, and it is a willing target for Dracula's bite attack.

Each time Dracula or his 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 Dracula is destroyed, is on a different plane of existence than the target, or takes a bonus action to end the effect.

Children of the Night (1/Day). Dracula magically calls 2d4 swarms of bats or swarm of rats, provided that the sun isn’t up. While outdoors, Dracula can call wolves instead. The called creatures arrive in 1d4 rounds, acting as allies of Dracula and obeying his spoken commands. The beasts remain for 1 hour, until he dies, or until he dismisses them as a bonus action.

The vampire 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. The vampire regains spent legendary actions at the start of its turn.

Move. The vampire moves up to its speed without provoking opportunity attacks.

Unarmed Strike. The vampire makes one unarmed strike.

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

Swift Spell. Dracula casts a spell of 4th level or below from his spell list without expending a spell slot or requiring verbal components

Mass Drain (Costs 2 Actions). All Creatures within 30 feet of Dracula must make a DC17 Constitution Saving throw or take 3d6 Necrotic Damage, or half as much on a successful save. Dracula gains temporary hitpoints equal to total damage dealt.

If reduced to 0hp or below Dracula regains 300 hit points, immediately uses his Demonic Megiddo and gains the following features

Demonic Megiddo (1/day). Dracula immediately casts Demonic Megiddo, without expending a spell slot, without requiring any components.

Haste. Dracula's Multiattack action is replaced with the following options.
Frenzied Multiattack (Vampire Form Only). Dracula makes three attacks, only one of which can be a bite attack.
Frenzied Casting (Vampire Form Only). Dracula casts a spell, then makes an unarmed strike..

Growth. Dracula grows to size large, standing around 12 feet tall. Dracula's Unarmed Strikes deal an additional 1d6 damage

Split Concentration. Dracula can concentrate on two spells at once, however, when he must make a constitution saving throw to maintain concentration on a spell, the DC is equal to 10 + the combined level of the spells, or half the damage taken, whichever is higher. Dracula can end one spell as a free action before rolling the saving throw to return to the normal rules for concentration checks.

Greater Spellcasting. Dracula gains 2 7th level spell slots, 1 8th level spell slot and 1 9th level spell slot.

Mythic Resistance (3/day). When Dracula fails a saving throw, he can instead choose to succeed.