Well, the world of fanfiction is vast. For Thorfinn Rowle and Hermione Granger, there are fanfictions that range from the very dark and angsty to more light - hearted and humorous takes. The better - written ones usually have a good understanding of the original characters' personalities. They might take liberties with the plot but still stay true to the essence of Hermione's intelligence and Rowle's more sinister nature in a creative way.