Adze

Shapechanger. If the adze isn't in sunlight or running water, it can use its action to polymorph into a Fine Firefly or a Medium cloud of mist, or back into its true form.

While in Firefly form, the adze can't speak, its walking speed is 5 feet, and it has a flying speed of 30 feet and one hit point. Its statistics, other than its size, hitpoints and speed, are unchanged. Anything it is wearing transforms with it, but nothing it is carrying does. It reverts to its true form if caught. If killed it turns into a cloud of mist and leaves. While in firefly form it can be identified with the spells faerie fire, detect evil, detect magic, detect poison and disease, locate creature, locate animals (by casting it on the firefly and it not being revealed), dispel magic, detect thoughts or true seeing.

While in Firefly form it can cast dancing lights, infest and charm person (children only)

While in mist form, the adze 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 (3/Day). If the adze fails a saving throw, it can choose to succeed instead.

Misty Escape. When it drops to 0 hit points outside its resting place, the adze 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 adze 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.

Regeneration. The adze regains 20 hit points at the start of its turn if it has at least 1 hit point and isn't in sunlight. If the adze takes radiant damage or damage from holy water, this trait doesn't function at the start of the vampire's next turn.

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

Malaria. Creatures bitten by the Adze or it's mosquito swarms and survive the encounter must make a con save, DC 18 against getting malaria. If they fail there are no immediate effects. The first symptoms show up it 1d3 days after bite. The symptoms are heaving sweating, fever, vomiting, shivering, and convulsions, bloody stool, coma and death. Once the symptoms show up the player takes 1d3 str, 1d3 con and 1 exhaustion point at the beginning of the day. The player cannot get hp or remove exhaustion points by resting. At the end of each day the player can get to make a another DC 18 con save. When the player makes three the dease has run it's course and the player can never be inflected again. A lesser restoration spell automatically gives one save to the player, a lesser restoration spell or heal spell cure it immediatly. Players then get back 1d3 stats per long rest.

Adze Weaknesses. The adze has the following flaws:

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

Stake to the Heart. If a piercing weapon made of wood is driven into the adze's heart while the vampire is incapacitated in its resting place, the vampire is paralyzed until the stake is removed.

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

Multiattack. (Adze Form Only). The vampire makes two attacks, only one of which can be a bite attack or a spell.

Unarmed Strike (AdzeForm Only). Melee Weapon Attack: +10 to hit, reach 5 ft., one creature. Hit: 8 (1d8 + 4) bludgeoning damage. Instead of dealing damage, the adze can grapple the target (escape DC 18).

Bite. (Adze Form Only). Melee Weapon Attack: +10 to hit, reach 5 ft., one willing creature, or a creature that is grappled by the adze, 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 adze 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 adze's control. Creatures bitten by the Adze and survive the encounter must make a con save, DC 18 against getting malaria.

Charm (adze or flyfire form). The vampire targets one humanoid it can see within 30 feet of it. If the target can see the vampire, the target must succeed on a DC 20 Wisdom saving throw against this magic or be charmed by the vampire. The charmed target regards the vampire as a trusted friend to be heeded and protected. Although the target isn't under the vampire's control, it takes the vampire's requests or actions in the most favorable way it can, and it is a willing target for the vampire's bite attack. While in firefly from it can only charm children.

Each time the vampire or the vampire's 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 the vampire 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). The vampire magically calls 2d4 swarms of bugs or 1d3 swarms of mosquitoes.

Spell casting +10 to attack rolls, DC 10 Saves

Cantrips: Poison Spray, Infest, Druid craft

1st level (4 per long rest): Faerie Fire, Fog Cloud, Speak with Vermin,

2nd level (3 per long rest: Hold Person, Pass with out Trace, Moon beam

3rd level  (3 per long rest): Dispel Magic

4th level (once per long rest): Blight, Giant Insects

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

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

Unarmed Strike. The adze makes one unarmed strike.

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