Volenta Popfsky

Bride of Strahd. While Strahd can take Lair Actions, Volenta can benefit from them. If Strahd chooses his first Lair action, Volenta can pass through solid walls, doors, ceilings, and floors as if they weren't there. She only has this ability so long as Strahd allows her to have it.

Shapechanger. If the vampire isn't in sunlight or running water, it can use its action to polymorph into a Tiny bat or 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. 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 (1/Day). If the Volenta fails a saving throw, she 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.

Mourning Amulet. Any damage that Volenta takes is transferred to the Mourning Amulet. If the amulet absorbs damage that reduces it to 0 hit points, it is destroyed, and Volenta takes any leftover damage. The Mourning Amulet has 20 hit points and is restored to that number of hit points each dawn, provided it has at least 1 hit point remaining.
If the Mourning Amulet is broken, she goes into a bloodlust and is considered to be under the effects of non-magical Haste spell for 1 minute.

Regeneration. Volenta regains 15 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.

Assasinate. During her first turn, Volenta has advantage on attack rolls against any creature that hasn't taken a turn. Any hit Volenta scores against a surprised creature is a critical hit.

Evasion. If Volenta is subjected to an effect that allows her to make a Dexterity saving throw to take only half damage, Volenta instead takes no damage in she succeeds on the saving throw, and only half damage if she fails.

Sneak Attack (1/Turn). Volenta deals an extras 14 (4d6) damage when she hits a target with an attack and has advantage on the attack roll, or when the target is within 5 feet of an ally of Volenta that isn't incapacitated and Volenta doesn't have disadvantage on the attack roll.

Blood Frenzy. Volenta has advantage on melee attack rolls against any creature that doesn't have all its hit points.

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

Vampire Weaknesses. The vampire has the following flaws:

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

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

Stake to the Heart. Volenta is destroyed if a piercing weapon made of wood is driven into its heart while it is incapacitatedin its resting place.

Sunlight Hypersensitivity. Volenta takes 20 radiant damage when it starts its turn in sunlight. While in sunlight, it has disadvantage on attack rolls and ability checks.

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

Claws (Vampire Form Only). Melee Weapon Attack: +7 to hit, reach 5 ft., one creature. Hit: 9 (1d8 + 4) slashing damage. Volenta can grapple the target (escape DC 18).

Bite. (Bat or Vampire Form Only). Melee Weapon Attack: +7 to hit, reach 5 ft., one willing creature, or a creature that is grappled by Volenta, incapacitated, or restrained. Hit: 7 (1d6 + 4) piercing damage plus 10 (3d6) 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.