The crystal took on a turquoise tint. The lid rose higher, revealing the figure within. Another giant, though not so tall as Gadreel. A woman. The fine crystalline tendrils wrapping her body began to retreat, exposing bare pale skin. Nina felt a frisson of primal fear at the sight of her face. Though she had the same non-human features as her husband, she was beautiful – in the dangerous, predatory manner of a lioness or a bird of prey. Nina’s unease was compounded by the Nephilim’s hair. It was red, like hers – but of a shade no human had ever naturally worn, almost the colour of blood.

Gadreel made a deep, breathless sound, his expression beatific. ‘Sidona,’ he said, putting a hand on the motionless body.

‘Sidona – my wife,’ echoed Zan.

‘Yeah, I figured that part out for myself,’ Nina snarked.

‘The high priestess of the Nephilim,’ he continued. ‘She is safe, and now she will awaken the rest of my people.’

‘Okay, great,’ she said with forced cheer. ‘Well, if he doesn’t need me any more, I’ll be on my way!’

Gadreel looked at her with annoyance, pointing at the key. ‘You will wake my son, Turel, then my warriors. She will take . . . I think he means a few minutes,’ Zan said, ‘to recover.’

Nina reluctantly returned to the coffin, but other than an unpleasant bleach-like odour, the air was clear of residual gas. She took the key and went to the third central sarcophagus. The shadowy form inside was almost as tall as Gadreel, but even through the distorting crystal it was noticeably more slender, wiry rather than muscular. Under Gadreel’s watchful stare, she activated the key.

Again a new eye opened inside her mind, drawing her into the strange parallel realm of energy. This time, the process of awakening the sleeper was almost routine. She took a moment to widen the scope of her perception, trying to feel the fortress itself. The result was unnerving. The forces lifting its mass clear of the ground in defiance of gravity were vastly more powerful than she had imagined.

Could she affect them? Not from here, she realised. The key was merely a conduit, while the central altar in the throne room was indeed a kind of a control panel, intimately linked to the fortress’s levitation.

Shifts in the energy flow brought her mind back to more immediate matters. She released the key, drawing back from the opening sarcophagus. Gadreel leaned over Sidona’s coffin. The glassy strands enveloping the Nephilim woman had now fully withdrawn, patches of warmer colour appearing on her pallid skin.

He glanced impatiently at Nina. ‘Now wake my warriors,’ Zan intoned from the stairs.

The revival process became practically rote, setting several more Nephilim on the road to recovery. She released the key – to find another person in the chamber. Sidona was now standing, her back to Nina as she donned a long purple robe.