Vampire Blood Knight

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

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 (3/Day). If the vampire fails a saving throw, it 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.

Regeneration. The vampire regains 20 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.

Spider Climb. The vampire 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. The vampire can’t enter a residence without an invitation from one of the occupants.

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

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

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

 Ambusher. The vampire adds 1d8 to any Dexterity (Stealth) check or initiative roll.

Grim Executioner. If the vampire makes a critical hit, and the target has a lower hit point total than two times their character level (for player characters) or challenge rating (for non-player characters), they are killed outright. If the hit point total is higher than that level, the vampire instead deals an additional 21 (6d6) damage of the same type as the weapon.

Know Your Enemy. After spending at least 1 minute observing or interacting with another creature outside combat, the vampire can learn certain information about its capabilities compared to the vampire's own. In terms of characteristics, the vampire learns whether two of the following are superior, inferior, or equal to its own: the target creature's Strength score, Dexterity score, Constitution score, Armor Class, current hit points, total class levels (if any) and fighter class levels (if any). If one of the characteristics is inapplicable, it cannot be chosen.

Multiattack. The vampire makes two greatsword attacks.

Greatsword. Melee Weapon Attack: +9 to hit, reach 5 ft., one creature. Hit: 11 (2d6 + 4) slashing damage.

Summon Steed. The vampire can call forth a nightmare, as per find steed, at will, using it as a steed.

Unarmed Strike (Vampire Form Only). Melee Weapon Attack: +9 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).

Disarming Attack (4/Day). When the vampire hits a creature with a weapon attack, it can attempt to disarm the target, forcing it to drop one item of the vampire's choice that it’s holding. The target must make a DC 17 Strength saving throw. On a failed save, it drops the object. The object lands at the target's feet.

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. 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 17 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.

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 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.

Blood Knight Training. The vampire is adept in the ways of combat, and knows a variety of combat stances. It can change between these, or exit one.

Offensive. While in this stance, the vampire deals an additional 3 (1d6) of the damage type of its weapon when it strikes.

Defensive. While in this stance, the vampire can add its full Dexterity modifier to its AC.

Accuracy. While in this stance, the vampire can add its Charisma modifier to any ranged weapon attacks. Additionally, it can add its Dexterity bonus to the attack and damage rolls of any melee weapon with the slashing damage type.

Grappling Strike. Immediately after the vampire hits a creature with a melee attack on its turn, it can try grapple the target as a bonus action.

Unearthly Reflexes. On a Dexterity saving throw, the vampire can take half damage on a failed save, or no damage on a successful save.

Brace (4/Day). When a creature the vampire sees moves into the reach the vampire have with the melee weapon it is wielding, it can use its reaction to make one attack against the creature, using that weapon, adding 1d8.

Cruel Riposte (4/Day). Whenever a creature within 5 feet of the vampire makes an attack against it, it can make a melee attack against the attacking creature.

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

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

Unarmed Strike. The vampire makes one unarmed strike.

Change Stance. The vampire can change its combat stance.

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