wardens fear bob

"Nor would I," Luccio said. "That could be a true nightmare. All that knowledge, without conscience to direct it. The necromancer Kemmler had such a spirit in his service, a sort of miniature version of the Archive. Nowhere near as powerful, but it had been studying and learning beside wizards for generations, and the things it was capable of were appalling. " She shook her head.
I took a sip of tea, because otherwise the gulp would have been suspicious. She was talking about Bob. And she was right about what Bob was capable of doing. When I'd unlocked the personality he'd taken on under some of his former owners, he'd nearly killed me.
"The Wardens destroyed it, of course," she said.
No, they hadn't. Justin DuMorne, former Warden, hadn't destroyed the skull. He'd smuggled it from Kemmler's lab and kept it in his own-until I'd burned him to death, and taken it from him in turn.
"It was just too much power under too little restraint. And it's entirely possible that the Archive could become a similar threat on a far larger scale. I know you care about the child, Harry. But you had to be warned. You might not be doing her any favors by acting like her friend. "


Small Favor Chapter 46, Page 408-409