Darkforged Weapon

Paranoid and malign, the Daemonsmiths of the Chaos Dwarfs often retain their most potent work for their own use. These 'Darkforged' weapons can vary in style and shape according to the whim of their creator, as can the abilities granted to them by the twisted runes and nightmarish infusions bound within them.

Source

 * Tamurkhan: The Throne of Chaos
 * pg. 171