Propugnator

Propugnators were interdimensional “professional avengers”.

When hired by someone who harboured vengeful feelings towards another, they would take over not only the physical carrying out of vengeance, but absorb the feeling of vengefulness itself, guaranteeing both that the implemented revenge would be heartfelt, and that the original hirer could regain their peace of mind without giving up on having their revenge. Propugnators typically wore long brown coats and pilgrim-type hats.

Wendy VII met a Propugnator called Jark Haine during her first visit to Hilbert's, being intensely creeped out by the whole idea. (PROSE: The Grand Multiverse Hotel)