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

Vampiric Nature. Strahd is a vampire, and he has the abilities typical to a regular vampire and suffers the same weakness. These are listed in his Characteristics.

Regeneration. Strahd regains 20 hit points at the start of his turn if he has at least 1 hit point and isn't in running water or sunlight. If he takes radiant damage or damage from holy water, this trait doesn't function at the start of his next turn.

Martial Prowess (1/Turn). When Strahd hits a creature with a melee weapon attack, the attack deals an extra 7 (2d6) damage of the weapon's type, and the creature must make a DC 18 Strength saving throw. On a failure, Strahd can push the creature up to 10 feet away from it, knock the creature prone, or make the creature drop one item it is holding of Strahd's choice.

Might of Vampyr (Recharges after a Short or Long Rest). If Strahd would be reduced to 0 hit points, his current hit point total instead resets to 150 hit points, he recharges Rotten Fate, and he regains any expended uses of Legendary Resistance. Additionally, Strahd can now use the options in the "Mythic Actions" section for 1 hour. Award a party an additional 15,000 XP (30,000 XP total) for defeating Strahd after Might of Vampyr activates.

Multiattack. Strahd makes three attacks, only one of which can be a Bite attack. Alternatively, Strahd uses Spellcasting then makes a Longsword attack.

Bite. Melee Weapon Attack: +10 to hit, reach 5 ft., one target that is grappled, incapacitated, or restrained by Strahd. Hit: 12 (2d6 + 5) piercing damage. If the target is a living creature, it loses 14 (4d6) hit points and its hit point maximum is reduced by an amount equal to the hit points it lost, and Strahd regains the same number of hit points. The target dies if its hit point maximum is reduced to 0. A creature slain in this manner rises as a vampire spawn under Strahd's control the following night.

Claw. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 8 (1d6 + 5) slashing damage plus 9 (2d8) necrotic damage. If the target is a creature, Strahd can grappled it (escape DC 18) instead of dealing the slashing damage.

Longsword. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit: 9 (1d8 + 5) slashing damage plus 9 (2d8) necrotic damage.

Spellcasting. Strahd casts one of the following spells, requiring no material components and using Intelligence as the spellcasting ability (save DC 18):

At will: mage hand, prestidigitation, toll the dead (3d8 or 3d12)
3/day each: animate dead (as an action), comprehend languages, detect magic, detect thoughts, fog cloud, greater invisibility, nondetection, polymorph
1/day each: animate objects, create undead (as an action), fireball, scrying (as an action)

Charm. Strahd targets one humanoid he can see within 30 feet of him. If the target can see Strahd, the target must succeed on a DC 18 Wisdom saving throw against this magic or be charmed. The charmed target regards Strahd as a trusted friend to be heeded and protected. The target isn't under Strahd's control, but it takes Strahd's requests and actions in the most favorable way and lets Strahd bite it. Each time Strahd 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 Strahd is destroyed, is on a different plane of existence than the target, or takes a bonus action to end the effect.

Rotten Fate (Recharge 6). Starhd targets a creature he can see within 120 feet of him, and a sickly green ray envelops the creature. The target must make a DC 18 Constitution saving throw taking 57 (6d8 + 30) necrotic damage on a failed saving throw, or half as much damage on a successful save. If the damage dealt would reduce the target to 0 hit points, it dies and rises as a strahd zombie under Strahd's control at the start of his next turn.

Shadow Step. Strahd and anything he is wearing or carrying teleport to an unoccupied space he can see within 60 feet of him that is within dim light or darkness.

Children of the Night (2/Day). Strahd magically calls 2d4 swarms of bats or swarms of rats, provided that the sun isn't up. While outdoors, Strahd can call 3d6 wolves instead. The called creatures arrive in 1d4 rounds, acting as allies of Strahd and obeying his spoken commands. The beasts remain for 1 hour, until Strahd dies, or until he dismisses them as a bonus action.

Parry. Strahd adds 5 to his AC against one melee attack that would hit him. To do so, Strahd must see the attacker and be wielding a melee weapon.

Strahd can take 3 legendary actions, choosing from the options below. Only one legendary action can be used at a time and only at the end of another creature's turn. Strahd regains spent legendary actions at the start of his turn.

Move. Strahd moves up to his speed without provoking attacks of opportunity.

Strike. Strahd makes a Claw attack.

Bite (Costs 2 Actions). Strahd makes a Bite attack.

If Strahd's Might of Vampyr trait has activated within the last hour, he can use the options below as legendary actions.

Vile Wizardry (Costs 2 Actions). Strahd uses Spellcasting.

Necromantic Might (Costs 3 Actions). Strahd recharges, and uses Rotten Fate.