I was thinking of this one, the death of Erebus in Capo IV.

However, when I went to read it after deciding to make this thread, I found that it was much shorter and less detailed than I had thought, meaning I must have heavily elaborated my memory of it over the years. Nevertheless, it's still a great piece of work and I can't think of any that I've enjoyed quite as much. Who wrote it, anyway, between co-hosts GH and Khaan, and thePizza?