Ability Score Increase. Your Charisma increases by 2, and your Intelligence increases by 1.
Age. Vampires are said to be immortal and there are no recorded cases of a vampire dying of old age. You don't physically age either and appear as the age you were when you turned.
Alignment. While vampires have no innate tendency toward evil, having to feed on the living pushes them toward such. Regardless of morals, vampires are lawful.
Size. Vampires are the same build and size as humans. Your size is Medium.
Speed. Your base walking speed is 30 feet.
Type. Your creature type is undead, rather than humanoid.
Darkvision. Being a creature of the night, you have superior vision in dark and dim conditions. You can see in dim light within 120 feet of you as if it were bright light, and in darkness as if it were dim light. You can't discern color in darkness, only shades of gray.
Strength of the Dead. You have resistance to necrotic damage.
Immortality.
You do not die from normal means. If you would die and are outside of your resting place, you transform into a cloud of mist (as in the Shapechanger trait), provided that you aren't in sunlight or running water. If you can't transform, you are destroyed.
While you have 0 hit points in mist form, you can't revert to your vampire form, and you must reach your resting place within 2 hours or be destroyed. Once in your resting place, you revert to your vampire form. You are then paralyzed until you regain at least 1 hit point. After spending 1 hour in your resting place with 0 hit points, you regain 1 hit point.
Regeneration. You regain 5 hit points at the start of your turn if you have at least 1 hit point and aren't in sunlight or running water. If you take radiant damage or damage from holy water, this trait doesn't function at the start of your next turn.
Bloodthirst. You can use your action to drain blood and life energy from a willing creature, or one that is grappled by you, incapacitated, or restrained. Make a melee attack against the target. If you hit, you deal 1d6 piercing damage and 2d6 necrotic damage. The target's hit point maximum is reduced by an amount equal to the necrotic damage taken, and you gain 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.
Spider Climb. You have a climbing speed equal to your walking speed.
Shapechanger.
If you aren't in sunlight or running water, you can use your action to polymorph into a Tiny bat or a Medium cloud of mist, or back into your true form.
While in bat form, you can't speak, your walking speed is 5 feet, and you have a flying speed of 30 feet. Your statistics, other than your size and speed, are unchanged. Anything you are wearing transforms with you, but nothing you are carrying does. You revert to your true form if you die.
While in mist form, you can't take any actions, speak, or manipulate objects. You are weightless, have 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 you can't pass through water. You have advantage on Strength, Dexterity, and Constitution saving throws, and you are immune to all nonmagical damage, except the damage you take from sunlight.
Vampire Law. You have the following flaws:
Languages. You know the languages you knew in life.