Drach'nyen

Description
A mighty two-handed daemon blade, Drach'nyen is comprised of a single, impossibly sharp blade made of an unknown metal, its length etched with blasphemous runes. The blade periodically shifts, revealing the faces of every victim its wielder has slain, and thus become trapped within the blade and eternally devoured by the dark intelligence that resides within. The weapon has no set appearence when in realspace, and constantly shifts size and shape, with teeth and spines of abominable chitin forming along its length, and the colour and texture of its material changing from hard and brittle to sleek and unnatural.

History
An ancient and powerful blade, birthed when the first ancestor of man willingly killed his own brother, becoming the first act of murder that has forever damned the species (possibly alluding to Cain and Able), it is potent enough to exist independently outside of the influence of the Chaos Gods, and its name is whispered fearfully by daemons and beings of the Materium alike.

Powers
Drach'nyen is able to sunder the material realm around it, creating rifts in realspace that can reduce lesser minds to babbling madness. It is able to destroy ethereal and/or incorporeal beings that exist outside of the laws of physics (A.K.A. Daemons), with each soul taken only adding to the power of the daemon that resides within the blade. However, such a weapon can only be wielded by those with an exceptionally strong will and a high power level of their own, lest they be consumed by the blades will and their souls added to its tally.