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

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

Sneak Attack. Once per turn, the assassin deals an extra 14 (4d6) damage when it hits a target with a weapon attack and has advantage on the attack roll, or when the target is within 5 feet of an ally of the assassin that isn't incapacitated and the assassin doesn't have disadvantage on the attack roll.

Shapechanger. If Wyatt 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, Wyatt can't speak, his 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. he reverts to his true form if he dies.

While in mist form, Wyatt 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.

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

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

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

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

Reliable Talent.  Wyatt has refined his chosen skills until they approach perfection. Whenever you make an ability check that lets add proficiency bonus, he can treat a d20 roll of 9 or lower as a 10

Vampire Weaknesses. Wyatt has the following flaws:

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

Harmed by Running Water. Wyatt 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 Wyatt's heart while Wyatt is incapacitated in his resting place, Wyatt is paralyzed until the stake is removed.

Sunlight Hypersensitivity. Wyatt 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). Wyatt makes two attacks, only one of which can be a bite attack.

Shortsword (Vampire Form Only). Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) piercing damage, and the target must make a DC 15 Constitution saving throw, taking 24 (7d6) poison damage on a failed save, or half as much damage on a successful one.

Unarmed Strike (Vampire Form Only). Melee Weapon Attack: rollable]+9;{"diceNotation":"1d20+9","rollType":"to hit","rollAction":"Unarmed Strike"}[/rollable] to hit, reach 5 ft., one creature. Hit: 8 (1d8 + 4) bludgeoning damage. Instead of dealing damage, the vampire can grapple the target (escape DC 18).

Bite. (Bat or Vampire Form Only). Melee Weapon Attack: +9 to hit, reach 5 ft., one willing creature, or a creature that is grappled by the vampire, 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.

Charm. Wyatt targets one humanoid it can see within 30 feet of it. If the target can see Wyatt, the target must succeed on a DC 17 Wisdom saving throw against this magic or be charmed by Wyatt. The charmed target regards Wyatt as a trusted friend to be heeded and protected. Although the target isn't under Wyatt's control, it takes Wyatt's requests or actions in the most favorable way it can, and it is a willing target for Wyatt's bite attack.

Each time Wyatt or the 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 Wyatt 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 bats or rats, provided that the sun isn’t up. While outdoors, the vampire can call 3d6 wolves instead. The called creatures arrive in 1d4 rounds, acting as allies of the vampire and obeying its spoken commands. The beasts remain for 1 hour, until the vampire dies, or until the vampire dismisses them as a bonus action.

Cunning Action.  Wyatts quick thinking and agility allow him to move and act quickly. Wyatt can take a bonus action on each of his turns in combat. This action can be used only to take the Dash, Disengage, or Hide action.