Orastes, using the incantations of Skelos, used the Heart of Ahriman to give Xaltotun a semblance of life. Even Xaltotun, who owned the Heart three thousand years ago, did not know the full powers of the Heart. He did not invoke it, but merely guarded it so that it could not be used against him. Eventually the priesthood of Mitra acquired it and kept it hidden for three thousand years until Orastes' thieves stole it.
It is a cosmic source of power. Whence it came no one knows. Some say it is the heart of a god, others that it is a star that fell from the skies long ago. It is believed to have come from some far universe of flaming light, and against it the powers of darkness cannot stand, when it is in the hands of an adept white magician. It is like a sword that will smite at evil, and is not a sword with which evil can weild. It restores life, and it can destroy life.
It's powers are left for the individual DM to determine.
