but i see the 'comfort' part of fanfiction in it's predictability, not it's relationship with canon. suffering protagonist in hurt/comfort fiс would get comforted or healed, two lovers would get reunited, kinky relationship would work out for the best. even darkfics give what promised - you see the 'character death' warning, you know what you're going to get and what sort of emotional kick you're reading it for (and hence the importance of warnings and tags, the feeling of betrayal when you're not warned for something - i would accept tragic death in the book, but unwarned one in fic would get me enraged at the author, even if it would serve it's purpose in the story). it's less about relationship with source, or how much it strays from it or twists the original narrative, and more about underlying assumption that author would fulfill the promise of certain narrative.