Will healing

Marcone tilted his head slightly to regard Will. “What are you willing to pay for such information, young man?”
Will’s upper lip lifted away from his teeth. “How about I don’t tear you and your goons into hamburger?”
Marcone regarded Will for maybe three seconds, his face blank. Then he made a single, swift motion. I barely saw the gleam of metal as the small knife flickered across the space between them, and buried itself two inches deep in Will’s right biceps. Will let out a cry and staggered.
My own hands went toward my coat, but Gard had lifted a shotgun from behind a cabinet, and leveled it on me as my fingers touched the handle of my Sig. Hendricks had produced a heavy-caliber pistol from his suit, though he hadn’t aimed at anyone. I stopped, then moved my fingers slowly from my gun.
Will ripped the knife out of his arm, then turned to Marcone, his teeth bared.
“Don’t confuse yourself with Dresden, Mr. Borden,” Marcone said, his voice level and cold. His eyes were something frightening, pitiless. “You don’t have the power to threaten me. The instant you begin to change, Ms. Gard here will fire on Ms. Murphy—and then upon you.” His voice dropped to a barely audible murmur. “The next time you offer me a threat, I will kill you.”

Side Jobs, Aftermath, Page 369-370


I turned to Will and said, “Let’s take care of your arm.”
“It’s fine,” Will said.
“Don’t play tough guy with me,” I said. “Let me see.”
Will sighed. Then he took his hand away from the wound. There was a slit in his shirtsleeve, where the knife had gone in. It was too high up on his arm to make rolling the sleeve up practical, so I tore it a little wider and examined the wound.
It wasn’t bleeding. There was an angry, swollen purple line over the puncture mark. It wasn’t a scab, either. It was just . . . healing, albeit into a damn ugly scar.
I whistled softly. “How?”
“We’ve been experimenting,” Will said quietly. “Closing an injury isn’t really much different from shifting back into human form. My arm still hurts like hell, but I can stop bleeding—probably. If it isn’t too bad. We’re not sure about the limits. Leaves a hell of a mark, though.” His stomach gurgled. “And the energy for it has to come from somewhere. I’m starving.”
“Neat trick.”

Side Jobs, Aftermath, Page 373-374