Bob is scared of them

"I get the point," I said. I turned to a fresh page and from razor-sharp memory sketched out the symbol I'd seen on the demon Ursiel's forehead. "Do you recognize this?"
Bob's eyelights widened. "Are you insane? Harry, tear that paper up. Burn it."
I frowned. "Bob, wait a minute-"
"Do it now!"
The skull's voice was frightened, and I get nervous when Bob gets frightened. Not much can scare Bob out of his usual wiseass-commentator state of mind. I tore up the paper. "I guess you recognize it."
"Yeah. And I'm not having anything to do with that bunch."
"I didn't hear that, Bob. I need information on them. They're in town, they've taken a shot at me, and I'm betting they're after the Shroud."
"Let them have it," Bob said. "Seriously. You've got no idea the kind of power this group has."
"Fallen, I know," I said. "Order of the Blackened Denarius. But they have to play by the rules, right?"

Death Masks Chapter 8, Page 81-82