My first post and I'm already attempting to blow minds. Well, here goes...
First thing: I'm not sure if this is explained in Nightworld, which I understand is the last Repairman Jack book, before it technically ends. But assuming it's not, here it is: I think Jack is meant to be the Otherness's One. In Harbingers, The Lady says that all the crazy things that happened to Jack's loved ones was the Ally trimming his branches, but I think she was lying. I think it really was the Otherness. Consider: In Conspiracies, Jack has two nightmares, and in one of them the rakoshi kill Gia and Vicky, saying they were cutting Jack's ties to the world, and that he could finally be one of them. And then there were those crates, which I think were really sent to his hotel room because the Otherness wanted him to cross over and become indoctrinated.
Also, in Gateways, all those Everglades people were set to kill Tom. They were obviously being influenced by the Otherness, not the Ally, and they were trying to trim one of Jack's "branches" again. Look at Infernal, where the Lilitongue was first going to take Vicky, then Gia, then Jack himself! If that had happened, I think he would have been sent to the Otherness, cutting all of his branches in one fell swoop.
This kind of thing happens all the time in the Repairman Jack books.
Also, as a side note, I wanted to mention that in The Tomb, just after Jack lights the Mother on fire, it screams something that sounds like "Spa fon!" Could that be "Rasalom"?
Oh, and one more thing. Don't think you can pull a fast one on me, F. Paul Wilson! For those of you who haven't realized every single number- I repeat, EVERY SINGLE NUMBER- in Bloodline is a multiple of seven.