Molly fire wall

I looked up to find the turtlenecks advancing on us in a crowd, and I dismissed the sphere, landing in a crouch. I gathered more of my will together and swept my arm from left to right with a murmured word, and a second curtain of blue fire sprang up between me and the oncoming bad guys.
One of them gave the wall of flame a disdainful snort and calmly walked into it.
Like I said, I’m not much when it comes to illusions.
I am, however, reasonably good with fire.
The turtleneck didn’t scream. He didn’t have time. When fire is hot enough, you never really feel the heat. Your nerves get fried away and all you feel is the lack of signal from them—you feel cold.
He died in the fire, and he died cold. The cinder that fell backward out of the fire could never have been casually identified as human.
Now, that got their attention.
I stood there holding the fire against the remaining turtlenecks, the heat scorching away the thin layer of snow on the asphalt, then making it bubble and quiver, changing it into my own personal moat of boiling hot tar. It was hard work to keep it going, but I’ve never been afraid of that.
Harry, I need some room, came a thought from Molly, hardly able to be heard over the blaze of concentration necessary for maintaining the fire.
I gritted my teeth. It was like trying to hold an immensely heavy door open while half a dozen friends squeezed in around me. I felt an odd sensation and increased weariness and blocked them both away. I needed to focus, to hold the turtlenecks away from Molly.
Once again, the bad guys impressed me. They knew that an intense magical effort could be sustained for only a limited amount of time. They didn’t risk losing more men to the fire. Instead, they played it smart.
They just waited.
The fire blazed for another minute, then two, and as my control over it began to get shaky, something attracted my attention.


Ghost Story Chapter 22, Page 251-252