The night's dawn trilogy, book 3: The naked god
Peter F. Hamilton1999

Hell just went quantum . . .

TheConfederation is starting to collapse politically and economically, allowing the possessed to infiltrate more worlds. Quinn Dexter is loose on Earth, destroying the giant arcologies one at a time. As Louise Kavamagh tries to track him down, she manages to acquire some strange and powerful allies whose goal does not quite match her own. The campaign to liberate Mortonridge from the possessed degenerates into a horrendous land battle of the kind which hasn't been seen by humankind for six hundred years. Then some of the protagonists escape in a very unexpected direction . . .

Joshua Calvert and Syrinx now fly their starships on a mission to find the Sleeping God - which an alien race beleives holds the key to finally overthrowing the possessed.