Thankfully Kenning heard her. This was, after all, what she was trained for. She brought up her sword. Walden threw the full force of her own magic behind the Marshal as Kenning sliced through the white maggot-shapes—they withered into nothingness—and then slammed home a deep stab with the sword and a triple-strength banishment at the same time. For a moment the two of them worked in perfect harmony. YOU HAVE NO PLACE HERE, they roared at the demon. BEGONE.

And still it was not enough. The demon bent under the force of their attack, but its monstrous will clung firmly to the original pentagram. It wanted the mundane world. Oh, how it wanted. It wanted Chetwood, specifically: six and a half centuries of wild magic, plus a smorgasbord of half-trained teenage magicians and their untested strength. What demon could resist such a feast? And once it had consumed them all, what human power could contain it? It would swallow up Chetwood village, the meadows and ponds and little woodlands. From there it would spread its dark wings over the Home Counties. It would lift up its monstrous, writhing head, staring greedily southwards, scenting the air, tasting magic and complexity and systems and millions upon millions of selves. Then at last it would begin its slow oozing advance down the Great North Road, through the commuter towns one by one, vacuuming up the Green Belt, rolling over the traffic jams on the M25 without glancing down as the little cars buckled under the force of its passage and burst into flame, bent on the magnificent feast of London.

You’d get the full force of the RAF on you before you got close, thought Walden: but ‘nuclear strike on Hertfordshire’ was only a slightly less terrible an outcome than ‘capital city consumed by a higher demon.’

Minor possessions were common, but minor incursions—true manifestations of demons in the mundane world, reified, uncontrolled, wild—those were rare. Major incursions were very rare, and archdemonic incursions almost unheard of. This thing was bigger than an archdemon. Officially, those topped out at the ninth order. Tenth- and eleventh-order demons, theorised in the nineteenth century but not confirmed by experiment until the twentieth, were the higher demons—the principalities. The big boys, Walden’s thesis advisor had called them.

There was only one higher-demonic incursion in recorded history. It had followed an attempt at a twelfth-order summoning in the USSR in 1968. No one had tried a twelfth-order summoning since. Not officially, anyway.

BEGONE, BEGONE, BEGONE, chanted the combined force of Walden and Kenning, while the higher demon worried at the pentagram’s edges like a cat that had seen something small and tasty scuttling into the cracks of a crumbling brick wall.