Gregory Benford 
Great Sky River [EPUB ebook] 
Galactic Centre Book 3

The Family had never seen a manhunter like it. And when its machine-mind engulfed Cap’n Fanny, they knew Mantis was no simple killing-mech. A collector of human minds, a plunderer of living personalities, Mantis was a weaver of complex, murderous illusions. But why, Killeen wondered, did it indulge in such elaborate variations on slaughter when in a single blast it could destroy the remnants of Mankind?His answer lay waiting in Mantis’s extraordinary sensorium, in the museum of living ghosts and defiled spirits which drove the heart of the machine . . .