Bonded Mount. The knight is magically bound to a beast with an innate flight speed trained to serve as its mount. While mounted on this beast, the knight gains the beast’s senses and can't be knocked off the mount while conscious. The bonded mount obeys the knight’s commands. If its mount dies, the knight can train a new beast to serve as its bonded mount, a process requiring a month.
Sneak Attack. The knight deals an extra 7 (2d6) 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 knight that isn’t incapacitated and the knight doesn’t have disadvantage on the attack roll. This bonus damage doesn't add to bite attacks.
Regeneration. The knight regains 10 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 knight 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 knight can climb difficult surfaces, including upside down on ceilings, without needing to make an ability check.
Vampire Weaknesses. The knight 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 when it ends its turn in running water.
Stake to the Heart. The vampire is destroyed if a piercing weapon made of wood is driven into its heart while it is incapacitated in its resting place.
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.
Multiattack. The knight makes two attacks. Only one those can be his bite attack.
Shortsword. Melee Weapon Attack: +6 to hit, reach 5 ft., one target. Hit: 6 (1d6 + 3) piercing damage.
Lance. Melee Weapon Attack: +6 to hit, reach 10 ft., one target. Hit: 9 (1d12 + 3) piercing damage.
Claws. Melee Weapon Attack: +6 to hit, reach 5 ft., one creature. Hit: 8 (2d4 + 3) slashing damage. Instead of dealing damage, the vampire can grapple the target (escape DC 13).
Bite. Melee Weapon Attack: +6 to hit, reach 5 ft., one willing creature, or a creature that is grappled by the vampire, incapacitated, or restrained. Hit: 6 (1d6 + 3) piercing damage plus 7 (2d6) 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.
Uncanny Dodge. When an attacker the knight can see hits it with an attack, the knight can halve the damage against it.