Thanks to Paul for noticing and blogging this forum thread. Looks like the Avenger class in the 4th edition of Dungeons & Dragons was inspired by the main character Severian from the Book of the New Sun.
Mike Mearls writes:
Avenger: Ripping aside the ethereal nature of Wolf's Book of the New Sun and treating it as a comic book of sorts, Severian the torturer was a major influence on this class's initial feel and direction. Obviously its divine roots steered in a different direction, but I can easily see playing an avenger based on fantasy's most famous torturer.