Curse of Vampirism (HB)

You curse a Humanoid with restless death. The target's heart becomes frail and vulnerable. The next time the target drops to 0 Hit Points it dies outright, without rolling Death Saving Throws. If the target's body is not buried and bestowed proper funeral rites until the next dawn, it rises as an Umpyr.

Neonate. On the first night, the creature rises with a ravenous hunger. Its eyes darken, its reflection grows faint, and its blackened heart begins to beat anew. The creature's alignment shifts one step towards evil, as its morals grow insignificant when compared to the hunger. Its Strength, Dexterity, and Constitution scores each become 14, unless already higher. In addition, it gains one of the Vampire Weaknesses described in the Vampire statblock, at random. Henceforth, the cursed creature needs to consume some part of a living Humanoid, such as the blood, liver, or soul, in order to survive. If it refuses to feed, it suffers one level of Exhaustion at dawn, which lasts until it feeds or dies.

Fledgling. After the creature feeds for the first time, the Curse strengthens. Its alignment shifts one step towards evil, as its hunger becomes an all-encompassing torture, leaving room for little else. Its Strength, Dexterity, and Constitution scores each become 16, unless already higher, and it gains one additional Vampire Weakness. In addition, the cursed creature becomes resistant to Necrotic damage and gains Darkvision out to 120 ft. The cursed creature's type becomes Undead (Umpyr). It doesn't need to eat, drink, breathe, or sleep, and magic can't put it to sleep. It can finish a Long Rest in 4 hours if it spends those hours in an inactive, motionless state, during which it retains consciousness.

Umpyr. The second night the cursed creature feeds, its Curse latches on forever. Its Strength, Dexterity, and Constitution scores each become 18, unless already higher, and it gains the final two Vampire Weaknesses. The creature also gains the Vampire's Speeds, Traits, and Actions. It is proficient with the form's natural attacks, such as its bite or grave strike, which deal damage as shown in its statistics. From now on, in order to complete a Long Rest, the cursed creature must be lying on soil from the place where it first rose; otherwise it does not gain the benefits of resting. Only a Wish or its specific lifting conditions can undo the Curse at this point.