Blood Blade (5e Equipment)
From D&D Wiki
Weapon (Any Sword/Dagger), Very Rare (Requires Attunement)
This dull-looking blade appears black, but on closer inspection is actually very dark red. The handle is adorned with a single black crystal.
This blade radiates with dark magic. Inside the crystal is trapped the cursed soul of a powerful vampire. He will give the wielder great powers, but at a price.
Once attuned the wielder must perform a blood ritual to appease the vampire trapped within. To achieve this the PC must sacrifice 2hp per character level. This loss is permanent, even if they subsequently give up or lose the Blood Blade. Each time they go up a level they must sacrifice another 2hp permanently.
Only PCs or Neutral or Evil alignment may wield the Blood Blade. Any Good character will feel weak when picking up the weapon, and if they keep hold will lose 1d4hp per round until they let go.
When used in battle the Blood Blade adds +3 to Attack and Damage rolls. Each time they hit a living creature they regain 3hp. In addition, any Critical Hit on a living creature will allow the wielder to immediately regain lost hit points equal to the damage done.
Whilst holding the Blood Blade, no vampire will attack the wielder. Also, the wielder can Detect Evil and Good at will as per the spell while holding the weapon.