grendelkin illusion

I fell to the stone floor of the cavern in a heap. After that, my vision shrank to a tunnel and began to darken.
Which was just as well. Fewer distractions, that way. Now all I had to do was time it right.
A sound groaned down from the tunnel entrance above, an odd, ululating murmur, echoed into unintelligibility.
The furious grendelkin ripped the brush out of his arm and flung it away—but when he heard the sound, he turned his ugly kisser back toward the source.
I focused harder on the spell I had coming than upon anything I'd ever done. I had no circle to help me, lots of distractions, and absolutely no room to screw it up.
The strange sound resolved itself into a yowling chorus, like half a hundred band saws on helium, and Mouse burst out of the tunnel with a living thunderstorm of malks in hot pursuit.
My dog flung himself into the empty air, and malks bounded after him, determined not to let him escape. Mouse fell thirty feet, onto the huge pile of nesting material, landing with a yelp. The malks spilled after him, yowling in fury, dozens and dozens of malevolent eyes glittering in the light of the flare. Some jumped, some flowed seamlessly down the rough stairs, and others bounded forward, sank their claws into the stone of the far wall, and slid down it like a fireman down a pole.
I unleashed the spell.
"Useless vermin!" bellowed the grendelkin, its voice still pitched higher than before. He pointed at me, a battered-looking man in a long leather coat, and roared, "Kill the wizard or I'll eat every last one of you!"
The malks, now driven as much by fear as anger, immediately swarmed all over me. I gave them a pretty good time of it, but there were probably better than three dozen of them, and the leather coat couldn't cover everything.
Claws and fangs flashed.
Blood spattered.
The malks went insane with bloodlust.
I screamed, swinging wildly with both hands, killing a malk here or there, but unable to protect myself from all those claws and teeth. The grendelkin turned toward the helpless Elizabeth.
It was a real bitch, trying to undo the grendelkin's knotted ropes while still holding the illusion in place in my mind. Beneath the glamour that made him look like me, he fought furiously, clawing and swinging at the malks attacking him. It didn't help that Elizabeth was screaming again, thanks to the illusion of the grendelkin I was holding over myself, but hey. No plan is perfect.
"Mouse!" I cried.
A malk flew over my head, screaming, and splattered against a wall.
My dog bounded up just as I got the girl loose. I shoved her at him and said, "Get her out of here! Run! Go, go, go!"
Elizabeth didn't know what the hell was going on, but she understood that last part well enough. She fled, back toward the crude staircase. Mouse ran beside her, and when a malk flung itself at Elizabeth's naked back, my dog intercepted the little monster in the air, catching him as neatly as a Frisbee at the park. Mouse snarled and shook his jaws once. The malk's neck broke with an audible snap. My dog dropped it and fled on.
I grabbed my staff and ran to Gard. The malks hadn't noticed her yet. They were still busy mobbing the grendelkin—
Crap. My concentration had wavered. It looked like itself again, as did I.
I whirled and focused my will upon the giant pile of clean-picked bones. I extended my staff and snarled, "Counterspell this.

Side Jobs, Heorot, Page 143-144