In Novigrad I keep finding sheets of paper with messsages involving the "Eternal Fire" and Novigrad's church. They seem to be written by someone who is against Magic, Witches, Mages and anything involving the Conjunction (pretty much like the talk you usually skip when starting the game).
I remember I once found a corpse in a road and Geralt said: "It wasn't Nathaniel. S••t"
Nathaniel is Vegelbud's murderer that Geralt managed to track down and kill. Along with the corpse, another of those messages.
All of them are signed by a certain "- Concerned Citizen" and are named "Concerned Citizen Sermon" when in the Inventory. Apparently, they are even resellable!
Now, who is this guy? Does he appear in the game or he's just a kind of Easter Egg?