Sword of Sacrifice

Wondrous item (longsword), very rare (requires attunement)

After years of use during ritual bloodletting, this sword has absorbed necromantic powers that allow its wielder the ability to sacrifice their own life force to become more powerful. You gain a +1 bonus to attack and damage rolls made with this weapon.

Blood Sacrifice. If you are not Undead or a Construct and are below your hit point maximum, you can use your bonus action to draw this blade across your skin and imbue the blade with blood magic. Roll 1d8 and reduce your hit point maximum by that number. Your maximum hit points are restored following a long rest.

Additionally, on all successful attack rolls for the next minute, you deal additional necrotic damage equal to the 1d8 roll.