 The revelation of his status as the Blackstaff caused a temporary rift between Harry and Ebenezar, but this was ultimately mended after the events of "Proven Guilty".He has a long-standing unspecified disagreement with the Merlin, which has not been explored deeply within the series, though it is revealed in "Turn Coat" that they have known each other since McCoy was sixteen.It has been revealed that he mentored Harry's mother as well, and feels considerable guilt for having pushed her too hard and losing her to the other side.