The Hearth of the Dead is a side-quest in Hunted: The Demon's Forge during Chapter Four, Section 2. It is received from the Hearth itself.
Upon navigating within the burnt and crumbling courtyard you will find a fireplace with a skull embedded within the mantle. Upon activation it proclaims that he was imprisoned there by a evil warlock and requests that you bring him the various parts of his skeleton littered throughout the courtyard. Upon completing this task he will request that you will bring the resulting flame to his love on the other side on the wall. Once you climb the stairs you will see a metal grate and placed on the other side of the wall is an identical fireplace. Upon firing at the skull with the lighted arrow it will erupt in flames and a wall will move, revealing a couple of enchanted weapon racks that were seen through the grate. Upon activation the "love" will claim that she was the wife of the aforementioned warlock and his jealousy upon discovering her romance with his apprentice made him turn them into the Hearth of the Damned. She will offer, as a reward, her husband's greatest treasure hidden behind his "Black Heart". Upon re-entering that same courtyard you will find, to your far left on the left hand side, a building nearly demolished, with a shield emblazoned with a Black Heart affixed in the center of the far wall. The ruined wall in the way counts as cover, and can be hidden behind and then mounted in order to enter the room with the Black Heart. The wall with the Black heart is capable of being manipulated and pushed aside, revealing a lone Dragon's Tear.
Note: Within the courtyard is a corpse which the Deathstone can be used upon. He talks about two individuals betraying him and warns to beware of the Hearth of the Dead. By his Deathstone reflection you can assume he was the warlock.