I saw this story years ago on gurochan, either this or a previous incarnation, that was basically a Final Fantasy death battle (not sure if that was the actual title, it may or may not). It had like a bunch of Final Fantasy girls imprisoned and forced to fight duels to the death in a huge arena, (with some of them of course getting off on the killing/dying); I believe the plot later developed to center on Lightning and Terra, but the arena bits are probably the more memorable ones (and I think it was reasonably long too).