Introduction: Part two of a Harry Potter fanfiction based in J.K. Rowling's world, including some of her characters. 16 year old Catherine strives to do good despite the stigma surrounding her infamous family name, and Hogwarts House. She begins to discover there is a new powerful, dangerous enemy lurking within Hogwarts. Set in the time after Harry Potter's children have all grown up and left the school. See 'Diary of a Slytherin (Not Tom Riddle's) Pt 1' first. It has been split into two parts, as this part, due to mentions of the use of certain Unforgivable Curses being used at points throughout technically comes under 'sensitive content'....