merlin

She shook her head. “Have you noticed all the enchantments on the place?” Molly asked skeptically. “There is some really old stuff here that is still working.”
In point of fact, I had Bob going over the entire thing now for an in-depth assessment. The defensive systems built into the castle had been laid up by a wizard with a particularly thorough breed of the crazies. My first read was that Marcone’s use of them had only touched the surface of their potential—maybe Thorned Namshiel hadn’t yet had time to teach him to make full use of them. Hell, the only reason I felt like I knew what I was talking about was that the enchantments hardwired into the stones of the castle bore a startling structural resemblance to those that had been used to create Demonreach. It was entirely possible that the castle’s magical defenses had been the work of the original Merlin or one of his inheritors.
It would take time to be sure, but if I was right, by the time I was done with the place, I’d have a redoubt damned near as hard to crack as the island, and a heck of a lot more convenient to live in.
“Yeah. Kind of like having a smart house, I guess,” I said. “There’re all sorts of features I’m going to have to work through and figure out.”

Battle Ground Chapter 36, Page 385-384