Bran the Blessed's Cauldron

Origin
Bran the Blessed was a giant and king in Celtic mythology, appearing in the myth collection of the Mabinogion. The Irish king Matholwch sought a marriage alliance with Bran’s sister Branwen, which he approved and gave them a magic cauldron that could resurrect the dead. Content, the couple returned to Ireland and had a son Gwern, but Matholwch would abuse Branwen, tried to trick Bran into a trap and burned Gwern out of spite. Bran raised forces from Britain and fought against Matholwch’s troops. Noticing his former cauldron was being used to revive the enemy’s fallen, Bran hid among the dead to destroy the cauldron from the inside, sacrificing himself.

Bran’s head was removed from his failing body, as it was widely believed that the soul resided in the head. He was returned to Britain with the few survivors until he rested in silence at the White Hill. The present day location of the Tower of London, it is believed he would protect Britain from foreign invasion.

Effects
Contact with the body of a recently deceased person will create a living duplicate of the user, with the equivalent health and knowledge prior to their demise, with a few adjustments. Illnesses and permanent injuries will be weaker but the subject will still feel the same psychological effects as before. Contact with the living however will essentially extend their longevity, but not in the desired way. Whenever a fatal accident or natural demise occurs, the subject’s being will be collected into the head without the need of any other life support. Although able to stay alive barring heavy blunt force, their existence feels increasingly miserable until they fall completely silent and unresponsive.