Archduke Davnor of Avernus

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

While in bat or wolf form, Davnor can’t speak. In bat form, his walking speed is 5 feet, and he has a flying speed of 30 feet. In wolf form, his walking speed is 40 feet. His statistics, other than his size and speed, are unchanged. Anything he is wearing transforms with him, but nothing he is carrying does. He reverts to his true form if he dies.

While in mist form, Davnor 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 he can’t pass through water. He has advantage on Strength, Dexterity, and Constitution saving throws, and he is immune to all nonmagical damage, except the damage he takes from sunlight.

Devil’s Sight. Magical darkness doesn’t impede Davnor's darkvision.

Fiery Weapons. Davnor’s weapon attacks are magical. When he hits with any weapon, the weapon deals an extra 36 (8d8) fire damage (included in the weapon attacks below).

Innate Spellcasting. Davnor’s innate spellcasting ability is Charisma (spell save DC 26). he can innately cast the following spells, requiring no material components:

At will: alter self (can become Medium when changing her appearance), detect evil and good, fireball, invisibility (self only), wall of fire, scrying

3/day each: blade barrier, dispel evil and good, finger of death

Legendary Resistance (5/Day). If Davnor fails a saving throw, she can choose to succeed instead.

Magic Resistance. Davnor has advantage on saving throws against spells and other magical effects.

Regeneration. Davnor regains 40 hit points at the start of her turn. If she takes radiant damage, or is in sunlight this trait doesn’t function at the start of her next turn. Davnor dies only if she starts her turn with 0 hit points and doesn’t regenerate.

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

While he has 0 hit points in mist form, he can’t revert to his Archdevil form, and he must reach Avernus within 2 hours or be destroyed. Once in his Avernus, he reverts to his Archdevil form. He is then paralyzed until he regains at least 1 hit point. After 1 hour in his coffin with 0 hit points, he regains 1 hit point.

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

Vampire Weaknesses. Davnor has the following flaws:

Forbiddance. He can’t enter a residence without an invitation from one of the occupants.

Harmed by Running Water. He takes 20 acid damage if he ends his turn in running water.

Stake to the Heart. If a piercing weapon made of wood is driven into his heart while he is incapacitated in his coffin, he is paralyzed until the stake is removed.

Sunlight Hypersensitivity. While in sunlight, Davnor takes 20 radiant damage at the start of his turn, and he has disadvantage on attack rolls and ability checks.

Multiattack. Davnor attacks once with his bite and twice with Matalotok. He can substitute Horrid Touch for Matalotok.

Bite. Melee Weapon Attack: +17 to hit, reach 5 ft. Hit: 15 (2d6 + 9) piercing damage plus 24 (4d12) necrotic damage. The target’s hit point maximum is reduced by an amount equal to the necrotic damage taken, and Davnor regains hit points equal to that amount. The reduction lasts until the target finishes a long rest. The target dies if its hit point maximum is reduced to 0. A humanoid slain in this way and then buried in the ground rises the following night as a vampire spawn under Davnor’s control.

Charm. Davnor targets one humanoid he can see within 30 feet of him. If the target can see Davnor, the target must succeed on a DC 22 Wisdom saving throw against this magic or be charmed. The charmed target regards Davnor as a trusted friend to be heeded and protected. The target isn’t under Davnor’s control, but it takes Davnor’s requests and actions in the most favorable way and lets Davnor bite it.

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

Matalotok (Warhammer). Melee Weapon Attack: +17 to hit, reach 10 ft., one target. Hit: 17 (2d8 + 8) bludgeoning damage, or 19 (2d10 + 8) bludgeoning damage when used with two hands, plus 36 (8d8) fire damage. In addition, the weapon emits a burst of cold that deals 10 (3d6) cold damage to each creature within 30 feet of it.

Horrid Touch (Recharge 5–6). Davnor touches one creature within 10 feet of her. The target must succeed on a DC 26 Constitution saving throw or take 56 (10d10) necrotic damage and be poisoned for 1 minute. While poisoned in this way, the target is also blinded and deafened. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Teleport. Davnor magically teleports, along with any equipment he is wearing or carrying, up to 120 feet to an unoccupied space he can see.

Davnor can take 4 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. Davnor regains spent legendary actions at the start of her turn.

Immolating Gaze. Davnor turns her magical gaze toward one creature she can see within 120 feet of her and commands it to combust. The target must succeed on a DC 26 Wisdom saving throw or take 24 (4d12) fire damage.

Teleport. Davnor uses her Teleport action.

Bite (Costs 2 Actions). Strahd makes one bite attack.