"The Overseer?" I said. "Does that mean he's the one behind the Authorities?"

"No," said Pretty Poison. "He's much more powerful than that. He sits in judgement, and mercy and compassion are not allowed to him."

"I want to go home," said Madman.

"Most sensible thing you've said all day," said Sinner.

The stairs finally curved around a corner and came to an end, facing a great and elegant chamber carved out of crystal. A pleasant, comfortable light appeared suddenly overhead, bursting out of one crystal facet after another, until the whole chamber was bright as day, like standing in the heart of a huge diamond. In the centre of the crystal cave was a single raised slab of polished stone, and on that slab, sleeping peacefully, a man. He didn't look particularly dangerous, with his grey hair and grey robes, and a calm face apparently untroubled by care. We all filed into the shining chamber, looking uncertainly about us. I think we'd all been expecting more guardians, more defences, but everything was still and quiet. Like the eye of the storm.

Etched into every crystal facet were characters from the language known as Enochian, a tongue created for men to speak to angels. I recognised it, but I couldn't read it. Not many can. It is corrosive to rational thinking. Pretty Poison moved along one wall, tracing the characters with a fingertip.

"These are names," she said softly. "Names beyond number, of angels from Above and Below, from all ranks and stations ... Even my name is here. My true name, from before the Fall. No mortal should have access to this knowledge..."

"But... why write them here?" said Sinner.

"Because to know the true name of a thing is to have power over it," said Pretty Poison. "To command and to control. Whoever put the Lord of Thorns here, and made him Overseer of the Nightside, has given him power over all the agents of Heaven and Hell."

"No wonder he was ripping the wings off angels during the angel war," said Sinner. "But who could give him that kind of power?"

"Two possibilities come to mind," said Madman.

"Shut up," said Pretty Poison.

She sounded shocked, upset. I was concentrating on the man on the slab. He hadn't moved at all since we entered his domain. But I didn't think he was sleeping. Sleeping people usually breathe now and again. And then my heart missed a beat as he sat up abruptly, swinging his legs over the side of the slab, and sat facing us. We all froze where we were, caught in the gleam of his gaze, like burglars picked out by torchlight in a place they should never have entered. With his long grey robes, hair, and beard, the Lord of Thorns looked like nothing so much as an Old Testament prophet. The kind that told you the Flood was coming, and you'd left it far too late to book seats on the Ark. His face looked older than any man's should, and his eyes were fierce and wild and touched with a divine madness. His presence filled the crystal cave, and under his gaze we all flinched and felt unworthy.