Rerpf appears in The Colour of Magic as the newly appointed vice guildmaster in charge of tourism for the Guild of Merchants. Otherwise, he operates the Groaning Platter tavern by Brass Bridge. Accompanied by some trolls, he came to the Broken Drum to protect their interests- meaning Twoflower the tourist. Since tourism brings business, naturally the Merchants favor tourism, and are not happy to see Ankh-Morpork's first tourist about to get killed and robbed. In the end, he, his fellow Merchants, and his trolls get into a brawl with the Thieves and Assassins.
He commented how visitors would get the wrong impression of Ankh-Morpork with people robbing and murdering each other all over the place. He also mentioned that the city had many fine points of "historical and civic interest." Perhaps, then, he was one of the authors of the first edition of Wellcome to Ankh-Morporke, Citie of One Thousand Surprises?