Hermogënes was born with silver hair, which earned him the nickname "Harlock", meaning "white hair". After he became a lamplighter however, only those who had earned the right to call him by this nickname could do so. He also had very pale grey eyes that were nearly silver, as well as a prominent scar across his forehead.
Born in Seville, Hermogënes at some point emigrated to the Haacobin Empire and became a lamplighter. He rose to the highest enlisted rank of sergeant-master and was stationed at Wormstool, serving as its cot-warden.
Hermogënes was working alongside Major-of-House Thyssius Grystle when Rossamünd Bookchild and Threnody reported to their new post. He then showed them to their billets. Prior to Threnody's arrival Hermogënes was the best pirouette player at Wormstool. He was presumably killed during the Battle of Wormstool after the attacking monsters succeeded in gaining access to the upper floors of the cothouse.