On the far side was nothing but cold, bare metal.

The ancient magi who had built the Endurance would have recognised these halls. They were rusty, pockmarked by acid burns from the corrosive mists, but they lacked the fleshy vitality of other parts of the ship.

Mortarion emerged into a spire whose floors had been cored out to make a single, towering space. When completed, the alteration had sported decorative gargoyles, and fantastically detailed railings had edged the walkways formed by the edges of the removed floors. That was long ago. The statues were now nubs of iron, the railings dissolved to paper-thin fretting. The fog was at its thickest at the tower’s peak, where it formed clouds thick enough to rain. A light, acidic drizzle fell from on high. Puddles of it sat in concavities it had dissolved in the floor.

Mortarion stood at the base of the tower. With its interior structure removed, the true scale of an Imperial battleship was revealed. This single tower was a hundred metres across, and three hundred high. He raised his hands and tilted his face upwards. His yellow eyes closed, and he let the rain fall upon his face. It ran in greasy trails around the breathing mask embedded into his flesh.

With a gurgle of pleasure, Mortarion shook out his double wings. They resembled those of a giant fly, veined and diaphanous. After a couple of experimental twitches, Mortarion set them into blurring motion, and he rose smoothly from the ground.

His wings made a noise as loud as a hundred chainswords revving, but he moved serenely, his long robes trailing after him, dripping with the liquids they had accumulated on his walk through the ship.

He rose to the tower’s top where a pier extended from one wall. It was so corroded by the fog that it shook as he landed upon it. He folded his wings away back into his robe. As he walked the pier, it swayed and squealed, letting out a shower of rust, but it bore him surely, and he arrived at the door at the far end. Another pass of his hands sent the door grating into the wall. He went through onto a set of wrought iron stairs that curved up inside the skin of the spire. There were holes in the hull there through which shone the steady burn of stars. But the mist was unaffected; the air was unaffected; Mortarion was unaffected. Where decompression winds should rush, there was dank stillness. The Endurance no longer obeyed the strictures of reality.

A final door opened into the last chamber remaining in the tower. It had been in ages past the spire’s viewing dome. Now it was Mortarion’s horarium, his retreat, his sanctuary. A home away from home when he was forced to leave the comforting landscapes of the Plague Planet behind.