“Only one way it could have happened,” said William. “Someone gave themselves up willingly to possession. Just like the Kandarians.”

That stopped us all in our tracks for a while.

"A traitor in the family,” I said finally. “That’s easier to believe now, after all we’ve discovered about the Heart, and the Matriarchs, and the Zero Tolerance faction, but still . . . a Drood giving themselves up to a demon, and allying with soul-eaters? Why? What could they hope to gain?”

“More importantly,” Harry said slowly, “could there still be traitors, or possessed Droods, still operating inside the family? That could explain how we were so easily ambushed down on the Nazca Plain . . .”

William nodded sadly. “I was better off when I was crazy, and didn’t know what was going on . . . One thing seems regrettably clear. Ever since the Loathly Ones were let back in, for whatever reason, sixty years ago, they’ve been possessing victim after victim, slowly building their power and influence to the point where they could start building their structures again, and summon the Invaders.”

“There are reports coming in of more of these structures, in various stages of completion, from all across the world,” said Callan. “It’s like they’re not even trying to hide them anymore.”

“How many?” said the Sarjeant-at-Arms.

“Hundreds, so far. Wouldn’t surprise me if we ended up with thousands.”

“Let us discuss what we know of the Loathly Ones,” said William, in full lecture mode now. “They don’t just move in and take over their victims like most demons, or devils from Hell.” There was a slight pause while everyone looked at Roger, but he had nothing to say. William sniffed a few times, and then plunged on. “No; these demons infect their victims, through simple proximity. They implant a mental/spiritual embryo into the human body and soul. The invading presence then uses the human as food while the embryo gestates, before finally hatching into a complete Loathly One.

“Demonic cuckoos, as it were.

“First come physical changes. Warpings of the flesh, strange mutations in the body, all concerned with making the host strong enough to hold and contain the Loathly One embryo that’s forming. As this grows inside the host, it eats into the mind and soul, changing the thoughts and personality of the human host, who can feel themself going mad, becoming alien . . . but is helpless to stop or even slow the change. We can only imagine the kind of hell these poor unfortunates go through. Thoughts, emotions, beliefs, all change . . . until nothing is left but a new Loathly One drone. The human is gone, replaced.”

“So essentially,” I said, “once infected, their victims die by inches, day by day, losing every bit of themselves to become the thing that infected them. Just more drones for the Invaders. Right; that’s it. Kill the poor bastards on sight. No exceptions. We’ll be doing them a favour.”