Dumustas' Fang

Cursed Weapon (dagger), legendary (requires attunement)
Said to be made from the fang of Dumustas, an ogre vampire of legend. You gain a +1 bonus to attack and damage rolls made with this weapon. While attuned when you hit a living creature with it, that target takes an extra 2d6 necrotic damage, healing you for half (rounded up).
If you kill a living creature with this dagger they must make a DC 17 Constitution or Wisdom save (whichever is higher) or their soul is consumed by the dagger. If you are attuned then your lifespan increases by a number of months equal to their Constitution score. If your dagger consumes the soul of a creature with a higher Constitution score than you, then you have a 10% chance to increase your Constitution score by 1 (max 22). A soul devoured in this manner ceases to exist and does not travel to any afterlife. A creature whose soul has been devoured can not be resurrected.
Curse: This weapon is cursed, a fact that is not revealed when an identify spell is cast on the weapon or even immediately once you attune to it. Once you attune to this weapon you remain attuned until someone else attunes to it, but you can break the curse using the wish, miracle, or remove curse spells. A caster using the remove curse spell must cast it at 7th level or higher, if not then they must make a DC 17 ability check using their spellcasting ability to break the curse. If another creature kills you with Dumustas' Fang while you are cursed by it then you have disadvantage on your saving throw to prevent your soul from being consumed.
After a long rest make a DC 17 Wisdom save, failing this you must attempt to kill the nearest creature you see. If you don't see a creature, then you must immediately seek one out and then attempt to kill them. Dumustas' Fang will target sentient creatures first, but will be satiated by anything living. You are so compelled until you have killed a creature using Dumustas' Fang or you may also reattempt this saving throw once every hour. If Dumustas' Fang devoured a soul in the last 24 hours then you have advantage on this saving throw. If Dumastas' Fang has not inflicted necrotic damage to creature besides the wielder in the last 24 hours then you have disadvantage on your saving throw.

Source
Homebrew
Properties
Finesse, light, thrown (range 20/60)

Item type

Weapon, Melee

Rarity

legendary

Weight

1 lb