These 5 blades were forged for the infamous assassin Aenus Morganti for the assassination of the Emperor Selinious the 4th. They were forged from a combination of minthril and meteoric iron into knives suitable for stabbing and throwing. The knives are all the same size shape and weight, and thus are all but indistinguishable from each other. They are about 1 foot long from the tip of the blade to the end of the pommel, and the blades are made of highly polished metal.
The only really distinguishable feature of them, the one that sets them apart from other knives, is that when they are unsheathed you can feel it. When they are drawn, and while they out, everyone within a wide area will be chilled to the very bone, and not just the regular “brrr, I’m cold” type chill but the, “Hey look there is something wrong here” type chill. While they aren’t necessarily evil, except in the most black and white sense of the word, they are a very cruel way to die.
The reason for this is that they hunger. Not for blood like some blades, but for souls. They will literally consume the soul of anyone that is killed by one of them. They have a primal intelligence, if it can be called that, for its only purpose is to feed. They were made to prevent resurrection, without having to have a wizard spend minutes muttering his spells to prevent the resurrection of the person. By not only trapping the soul of their victim, but by destroying it entirely they prevent all forms of returning to life, save divine intervention.
However, magic is never free of sacrifice, and these are no different. If left unfed for to long they start drawing on the life force of those around them, causing mild dementias as parts of the victims’ souls are slowly torn from them, until only a burnt-out husk of what they once were is left. While they are not dead, they will have lost all will to live or to change, they will be unable to motivate themselves to do much, many even forgetting to feed themselves and dying from starvation or thirst. When they die they will be un-resurrectable, much like the more traditional victims of these blades.