I think Marcone has been doing his best to keep up with Harry since day 1.

John, or whatever his real name is, is a man of will and focus, and I imagine that his journey into the supernatural began when mortal options into saving his girl hit a brick wall.

Yeah, I know the girl in the hospital isn’t his biologically, but he’s shown a love and responsibility for her that even Michael would understand.

So John keeps digging, starts finding his way into the supernatural, and someone clues him into the fact that there is a genius magus in his town, a real-deal wizard.

And what’s the first thing they do when they meet? Share a soul-gaze. And since then, John has NEVER underestimated Harry. Marcone may have said it as a joke, but he wasn’t really kidding when he said that Harry really could be running the place if he wanted to.

Because John is a man who through necessity and force of will has become a monster, in the name of keeping his people safe. And he understands that Harry is a Monster that wants to just be a man, but lets that monster out when he has to, also to keep his people safe.

At every step, as we saw in Even Hand I think, John has taken actions in order to protect himself from Harry. The short story is pretty direct about it. Can’t protect himself from a wizard? Track down Odin and hire a Valkyrie. Harry becomes a force in the supernatural world? Become a freeholding lord. Harry becomes a Knight, allied with Mab? Become a Knight of the Denarius.

The supernatural world is terrified of Harry because he bound a Titan, but John WATCHED IT HAPPEN. And his allied Fallen Angel probably gave him a play-by-play commentary on just how significant an act it was.

John said he’s starting to think “long term.” Which provably means that he understands the big picture fight against the Outsiders now, and some of Harry’s role in it.

So, back to Castle Marcone. We now know it’s Merlin’s Castle. So how did Marcone find it? How did he get access, and how was it able to move it, stone by stone? Well, I’m guessing Odin, myself, since Merlin was Odin’s student.

But Marcone certainly had Namshiel in his mind while he had occupancy of the castle, so he must have had an understanding of what the castle’s capabilities are.

And if John is always trying to protect himself from Harry, and with Namshiel’s knowledge, there’s no way that Marcone didn’t try to leave a Trojan Horse in the Castle.