[Re. a Magneto/Xavier slashfic:]
M/X stories just can't end happily. Oh, there have been a few authors who've tried. There're even a few who have succeeded, except that even as you're reveling in the characters' apparent happiness, you can't silence the small voice in your head saying: "If you two knew what's coming..."
In this FF, Penknife doesn't try. We see Charles and Erik as they once were, but we also see the future coming in fast, like a fist, and we know how it will end. (For the record, in case you haven't been paying attention: in tears. Well, OK, actually in them developing major ideological differences and spending the rest of their lives on opposite sides battling each other for the title of King of the Mutants, but "in tears" is the short version. To the extent that there can ever be a short version in the Marvel universe.)