Walden nicked the tip of her left index finger and let a drop of blood fall towards the pentagram. The first layer of protections written into the summoning array went into action as it hit the ground, and the blood drop fizzled out of existence. Just the scent of it, the promise of human power and human vulnerability that it represented, would be enough to tempt a demon closer. Walden felt the inhabitants of the demonic plane notice what was happening and turn their attention to the classroom.

And then she summoned a demon of the fourth order.

She hardly needed the pooled power of the four students to support the invocation. She pulled some magic down from them through the array anyway, so they would know what it felt like, but fourth-order summoning was well within her capabilities. Demonic size in theory kept going forever in exponential progression, but in practice no one had ever found one bigger than the twelfth order. Only a handful of magicians in the world had ever summoned anything above the ninth.

Walden didn’t mention it often—after all, it was hardly relevant to a schoolteacher’s career—but she was, in fact, one of that handful.

She had to send her power diving through the demonic plane like a hook to scoop up a demon small enough for this pentagram. She felt the others scattering away from her in fear. In the real world Walden was a short thirty-eight-year-old white woman with mouse-brown hair in a neat bob. On the demonic plane she was a swaggering giant.

YOU, she said to her captured demon. COME.

The air over the pentagram boiled and split, glowing with the dull purplish light of a controlled demonic incursion. It was considerably more exciting-looking in the ultraviolet spectrum. The demon manifested, and as Walden moved power through the summoning array it began to shape itself not to the contours of possession but in a form of its own choosing. Reification, this was called. Not hugely attractive, it had to be said: the demon was about four feet high and consisted of an inkblot collection of wobbling black shapes, some of which might have been limbs. Halfway up there was a mouth, which opened to show serrated rows of needle teeth.

Query. Walden asked, “What is your name?”

The mouth let out a furious shriek, and the demon said, Vazirikal! Vazirikal!

Demon names were attached to them by humans and usually made useful handles to control them. “Thank you,” Walden said. With a hard downward slash of a hand gesture, she dismissed it. The inkblot shapes disintegrated. The purplish glow of incursion faded. The arcane lab was quiet. Walden’s students wore solemn expressions. Walden resisted the urge to glance over her shoulder at Kenning again.