A strange thirst grips the humanoid’s mind, and its skin turns milky white. It suffers a vulnerability to Radiance and while in sunlight, it has disadvantage on attack rolls and ability checks. After three days, a humanoid afflicted with this disease contracts Vampirism.
 
Vampirism. As a Vampire you are classed as Undead, you will not age past maturity, you can no longer eat or drink without incurring sickness but must feed on the blood of sentient living beings to survive. (Animal blood will surfice but nowhere near as effectively) Or else slowly succumb to feral vampirism. As a vampire gain Darkvision (Superior Darkvision if belonging to a race with Darkvision already). You also have Immunity to Disease (including lycanthropy, the Path of the Werewolf is locked to you.) and gain the Minor Illusion cantrip if you don't already know it. However, in direct sunlight, your Vampire blood boils. Causing a discomfort that exposes your vampric nature to all observers. This effect can be negated using the Disguise Self spell if you know it. While in direct sunlight, you also have disadvantage on attack rolls and ability checks. At all times, also suffer a Vulnerability to Radiance.
 
Vampires Bite. As a bonus action, any living creature within 5 feet that is grappled by you, incapacitated, or restrained, takes (1d4) piercing damage plus (1d6) necrotic damage. The target’s hit point maximum is reduced by an amount equal to the necrotic damage taken, and you regain 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. At 7th Level becomes (2d4) piercing damage plus (2d6) necrotic damage. At 11th level becomes (2d4+2) piercing damage plus (3d6) necrotic damage. Hits with this attack count as feeding and have a chance to cause sanguinare vampiris. 
 
Vampires Claws. Your unarmed strikes now deal (1d4) slashing damage and count as having light and finesse properties.