I think I'll post part of my B-K fic after all. Since it's a prologue, it should still be comprehensible outside of the intended context.
EDIT: I'm only putting the first few paragraphs here, to avoid spoilers.
Prologue
He existed at the edge of life. His sight faded in and out with every second; the images struggled into his perceptive range. All sound had been reduced to a dull hum, varying only slightly in levels of intensity. He lay as a shell of what he once was; holding him together were synthetic extensions of his solid form, so unnatural and yet inextricably part of him now. He lived, but he could never truly call himself complete in this condition.
The dreams were stronger than before. He could still see her eyes, fiercely alight reflecting the image of her deadly spell. Those were the only parts of her that were of flesh; the witch’s body had become little more than a skeleton sheathed in tattered cloth. Her lust of dark magic kept her alive, kept her conscious, and kept her wanting vengeance. Nothing would have swayed her from what she had planned and pondered after years of being buried under dense weight. She needed to destroy the duo that had set her under the ground to rot.
That is why it all had to happen, he realized. Only his essence could kill her—only by giving his life would she be defeated truly and forever. Without his willingness to stand up to the witch, all would have been lost. Yet… Here he was, splayed onto something rigid and smooth, barely keeping himself intact. He lived, but knew he would eventually lose his self.