scans illusion

"I didn't think you'd last this long," someone said.
I almost jumped out of my skin. I picked my staff up in both hands and turned in a slow circle, searching for the source of the voice. "Who's there?" There, to one side, a spot of cold - not physical cold, but something deeper and darker that my other senses detected. A pooling of shadows, an illusion in the darkness between lights, gone when lightning flashed and back again when it had passed.
"Do you expect me to give you my name?" the shadows scorned. "Suffice to say that I am the one who has killed you."
"You're an underachiever," I shot back, still turning, eyes searching. "The job's not done."
In the darkness underneath a broken streetlight, then, maybe twenty feet away, I could make out the shape of a person. Man or woman, I couldn't tell, nor could I distinguish from the voice. "Soon," the shape said. "You can't last much longer. My demon will finish you before another ten minutes have passed." The voice was supremely confident.
"You called that demon here?"
"Indeed," the shadowy shape confirmed.
"Are you crazy?" I demanded, stunned. "Don't you know what could happen to you if that thing gets loose?"
"It won't," the shape assured me. "It is mine to control."
I extended my senses toward the shape, and found that what I had suspected was true. It wasn't a real person, or an illusion masking a real person. It was only the seeming of one, a phantasm of shape and sound, a hologram that could see and hear and speak for its creator, wherever he or she was.
"What are you doing?" it demanded. It must have sensed me feeling it out.
"Checking your credentials," I said, and sent some of my remaining will toward it, the sorcerous equivalent of a slap in the face.
The image cried out in surprise and reeled back. "How did you do that?" it snarled.
"I went to school."


Storm Front Chapter 14, Page 173-174