I'm looking for something to read that's disturbing as Mathieu Bellamont's diary in Oblivion.

i find the lusty argonian maid to be the creepiest book in the game

Don't know about creepy, but Cicero's journal is pretty epic

There was a certain lighthouse near the NE corner of the map... I can't recall the name of... it was fairly creepy and had some uh creepy journals

frostflow lighthouse