Description
This spectral weapon, often employed by the wights and the undead, has been harnessed and bound to the realm of mortals and is now possible to wield by human hands. The weapon drains the soul from anyone its blade touches.
Notes
This weapon is much lighter than almost any other. It also deals corruption damage.
Source
The item can be looted from the following NPCs 
:
See Also
Repair
Legendary items cannot be repaired.
Dismantle
The Ghast Axe can be dismantled using the 
Dismantling Bench to recover the following materials:
For slightly more materials, you can use the 
Improved Dismantling Bench: