Legendary Resistance (1/day). If Vladimir would fail a saving throw, he can choose to succeed instead.

Regeneration. Vladimir regains 10 hit points at the start of its turn. If Vladimir takes fire or radiant damage, this trait doesn’t function at the start of Vladimir next turn. Vladimir body is destroyed only if he starts his turn with 0 hit points and doesn’t regenerate.

Rejuvenation. When Vladimir's body is destroyed, his soul lingers. After 24 hours, the soul inhabits and animates another corpse on the same plane of existence and regains all its hit points. While the soul is bodiless, a wish spell can be used to force the soul to go to the afterlife and not return.

Special Equipment. Vladimir wields a +2 greatsword with a hilt sculpted to resemble silver dragon wings and a pommel shaped like a silver dragon’s head clutching a black opal between its teeth

Turn Immunity. Vladimir is immune to effects that turn undead.

Oathbind. If Vladimir would deal damage to a dying creature with his +2 greatsword, he can instead choose to stabilize that creature and subject it to the effects of a geas spell. This geas lasts until dispelled and can damage its bearer any number of times each day. A creature that takes damage in this way is also restrained until the start of its next turn. In addition, the geas can’t be ended or dispelled except through the effects of a greater restoration or wish spell, or if Vladimir uses an action to dismiss it.

Burning Hatred. When Vladimir is reduced to 0 hit points, black flames erupt along the hilt of his greatsword and the shadows encircling its blade become spiked black wires. His statistics are then instantly replaced by the statistics of his second form. His initiative count doesn't change, excess damage doesn't carry over to his new form, and he retains none of the conditions he had in his previous form.

Multiattack. Vladimir makes two melee attacks. He can replace one of those attacks with a black flames attack.

+2 Greatsword. Melee Weapon Attack: +12 to hit, reach 5 ft., one target. Hit: 14 (2d6 + 7) slashing damage. Against Strahd, Vladimir deals an extra 14 (4d6) slashing damage with the weapon.
 Instead of pushing the target, Vladimir can force the target to make a DC 18 Strength saving throw or be knocked prone.

Black Flames. Ranged Spell Attack: +10 to hit, range 30 ft., one target. Hit: 7 (2d6) fire damage plus 3 (1d6) necrotic damage, and the target ignites in black flames. At the start of its next turn, the target and each creature within 5 feet of it must make a DC 17 Constitution saving throw or take an additional 7 (2d6) cold damage. (The flames can’t be doused by nonmagical means.)

Gravepyre. Vladimir hurls a magical ball of black flames that explodes at a point he can see within 120 feet of him. Each creature in a 10-foot radius sphere centered on that point must make a DC 17 Dexterity saving throw. The sphere spreads around corners. A creature takes 10 (3d6) fire damage plus 10 (3d6) necrotic damage on a failed save, or half as much damage on a successful one. On a failure, a creature also has disadvantage on the next attack it makes before the start of Vladimir’s next turn.

Destructive Wave. Vladimir strikes the ground with his greatsword, creating a burst of destructive energy that ripples outward from him. Each creature within 10 feet of him must succeed on a DC 18 Constitution saving throw or take 10 (3d6) thunder damage plus 10 (3d6) necrotic damage and be knocked prone. A creature that succeeds on its saving throw takes half as much damage and isn’t knocked prone.

Vladimir can take up to three reactions per round, but only one per turn. If Vladimir would lose his reactions and isn't incapacitated, he loses one reaction instead.

Vengeful Rush. In response to an enemy hitting or missing him with an attack, Vladimir charges toward it, moving up to 15 feet straight toward it without triggering opportunity attacks. If Vladimir ends his movement within 5 feet of that enemy, he can force it to make a DC 18 Strength saving throw. On a failure, the target takes 2d6 bludgeoning damage and Vladimir and the target move up to an additional 10 feet in the same direction without triggering opportunity attacks. If the target can’t move the full distance, it takes an additional 1d6 bludgeoning damage for each 5 feet not moved.

Vengeful Glare. In response to taking damage from an enemy within 30 feet, Vladimir forces that creature to make a DC 17 Wisdom saving throw. On a failure, the creature is frightened of Vladimir until Vladimir deals damage to it or until the end of Vladimir’s next turn. If the creature fails the saving throw by 5 or more, it is paralyzed instead.

Sentinel’s Strike. In response to a creature attempting to move out of his reach without first taking the Disengage action, Vladimir makes an attack against it with his +2 greatsword. On a hit, the creature takes no damage from the attack, but it falls prone and its speed becomes 0 for the rest of the turn.