Item from The Dresden Files by Jim Butcher
An ebony staff of unknown origin that allows its wielder to break the Laws of Magic without suffering the psychic corruption that normally accompanies black magic — carried by Ebenezar McCoy as the White Council's secret assassin.
The Blackstaff is an ebony staff — dark wood, smooth, unadorned except for the way it seems to absorb light rather than reflect it. It is carried by the Blackstaff of the White Council, currently Ebenezar McCoy, Harry's grandfather. The title and the weapon are the same: the Blackstaff is the White Council's sanctioned exception to its own Laws of Magic. The Laws of Magic are absolute. Kill with magic, and the psychic backlash warps your mind — you become a monster, inevitably, progressively, irreversibly. That's not a theory. That's observed magical physics. Every practitioner who uses magic to kill, mind-control, or perform necromancy begins a slide into madness and evil that has no known cure. The White Council enforces the Laws with execution precisely because the alternative is worse. Except for the Blackstaff. The ebony staff absorbs the psychic damage that should accompany violations of the Laws. Its wielder can kill with magic, can use entropic curses, can level buildings and assassinate targets — and the corruption flows into the staff instead of into the wizard's soul. The cost is visible: after heavy use, black veins spread up the wielder's hand and arm, staining the skin like ink spreading through water. It fades, eventually. Mostly. Ebenezar has used it to pull a decommissioned Soviet satellite out of orbit and drop it on a vampire stronghold. He has used it to kill. The White Council pretends the Blackstaff doesn't exist while relying on it for the dirty work that the Laws technically forbid. Harry discovered his grandfather's role and has not entirely reconciled himself to it.
A staff of pure ebony, featureless and dark. When used to break the Laws of Magic, it absorbs the psychic backlash — but stains the wielder's hand black. Ebenezar's hand is permanently darkened to the elbow.
Also known as: the Blackstaff, Ebenezar's staff, the ebony staff