Heart Eater

"There are fates worse than death" is a phrase that rings with far more weight in a world where the soul is a known quantity. While the exact nature of the afterlife eludes the understanding of mere mortals, they can be relatively certain that their soul being rent from their bodies and obliterated by a cursed blade is not a particularly ideal way to go.
Heart Eater was forged at a time when civilization was first developing in pockets of extraplanar space that was conducive to life. Originally, it was wielded as a ceremonial dagger by efreeti warlords who wanted to make a big show of sacrificing their rivals to absorb their power for themselves. Whether or not the blade was made to be sentient or developed its awareness over time is a matter for debate, but what became clear quite quickly is that its appetite had grown far beyond that of its wielders. 
The blade became infamous for driving its wielders to insanity; pushing their bloodlust farther and farther in an unending attempt to quench its thirst. 
Eventually, the blade was retired and passed down from efreeti to efreeti as a ceremonial item; never to be genuinely wielded in battle. Despite this, from time to time it tasted blood, as even from a mount on the wall it called to its owners and convinced them to wield it. 
In 1218 EP, Heart Eater found itself in the possession of a genasi freedom fighter called Nepheli, who reignited its insatiable calls for blood with a vengeance as she systematically hunted down the efreeti who ruled over the City of Brass  on the Plane of Fire. Together, they even made it into the very heart of the Efreeti Prince's palace (along with the aid of an adventuring party seeking to deal with the ramifications of The Extinction War), but she was ultimately convinced to part ways with the blade when she was shown what effect it was having on her. 
As of 1219 EP, Heart Eater is currently in the possession of the artificer Allston Preslet, who attuned to it "for scientific study and analysis). Only time will tell if the blade has the same effect on him as it did its countless wielders before him...

Mechanics & Inner Workings

The blade is infused with Animium (soul stone), which allows it to siphon the life force of those whose flesh it bites. Suitably strong or resilient creatures can resist this siphoning, but to the average humanoid, this blade is not to be trifled with.
In addition, the blade's imbued magic keeps its edge razor sharp, making it a far more effective weapon that a standard weapon-smith's work; meaning that even should its target survive the soul-siphon, they still need to worry about the lethal wounds the blade can easily inflict.

Item type

Weapon, Melee

Creation Date

unknown

Rarity

The efreeti crafted many ceremonial blades with magical properties in their time, but there are no others known to exist with Heart Eaters particular "quirks."