There are many accounts of this legendary blade; none are sure of its true properties.
Some say that it slays monsters with the weight of mundanity, and births them back into humanity; their hearts lurching to a start, blood stagnant in veins for centuries begins to move, as lungs long unused gasp out a single blessed breath.
Some say that it isn't to be used as a weapon; that that very act would be sacrilege of the highest order, that single strike slaying both the wielder and the one they struck. These scholars say that the blade was forged from the remnants of every blade that ever committed murder of their own volition.
It could be a schism in the fabric of is; an aberration that exists in its lack, taking the form of a blade to shield the pathetic minds of those that behold it, though it inevitably drives them mad.
Then, in some small cults to the east, they see the blade as a midwife, severing the histories of those struck to make the wielder their sole ancestor.
And, to one man, it is just a sword he carries at his side. There is nothing special about it. Nothing at all.