Currently Luciane’s Shadow.

Rune is Luciane Pendragon's shadow. He used a 9th level Modify Memory spell to attempt to erase the memory of several people but only succeeded to do two.
 
Not much is known about him other than he seems to have some knowlege about the destruction of Nillannas.
 
It was later discovered that the memories of him being murdered by Lucianne was fabricated by rune. In truth Lucianne was captured as a sacrifice in some strange ritual that went awry