Excerpt from Shadow Scythe
The Scythe was created in AD-1200 by a shadow mage and member of the Guardian Order know as the Hag. The Hag had been the wielder and protector of the Essence Stone of Shadow for nearly two hundred years and was known by many to be constantly running a plot of unknown goal. As a base for the weapon the Hag took the scythe owned by formed Death Angel host Veritas du Ciel that he had recently channeled some of his magic into to defend himself from the man sent to kill him. Using her power and the Essence Stone, the Hag summoned Veritas' soul from his fresh gravel immued both it and the stones power into what one once a simple farm tool. The Hag presented to Scythe to Tarah Vass in exchange for protecting Shinsou no Ten, Veritas' daughter and current host of Death Angel.