The terrible book known as the Book of Arkhan is said to have belonged to the infamous Arkhan the Black, greatest of Nagash's disciples. During the longs years of his tutelage, Arkhan kept extensive notes on his reviled experiments within the pages of this tome, and it is said that he still searches for it to this day. When its words are intoned, nearby Undead move with a vigour that defies belief.[1b]
This effect is achieved due to the book being primarily used to cast the Necromancy spell "Vanhel's Danse Macabre."[1b][1a]