Great Omenkiller Cleaver

Obtaining

 * Received after defeating the Omenkiller and Miranda, the Blighted Bloom boss in Perfumer's Grotto (Altus Plateau).
 * Guaranteed one-time drops from both of the Omenkillers located in Volcano Manor.
 * The first is in the courtyard west of the Prison Town Church site of grace.
 * The second is in a room one floor above the Guest Hall site of grace, accessed by dropping to an open door on the west side from the building's roof.