Sygnus - The major brushes I used were Standard, Clay, Clay Buildup, Dam Standard, Displace, Inflate, Rake, Slash1, Slash2, and of course, Smooth. (The painting was done with Standard and Pen Wet)
The scratches over the eyes, and really any deep claw style cut was done with the Slash1 brush. I’d make a cut, then smooth it over a bit. Smoothing helped because it will pull open the wound more.
The crackled skin and the wrinkles on the chest were done with the Displace brush, DragRect, and an alpha map. My alphas were mostly gathered from Aaron Sims Zbrush Alpha Library.
The noise in the mouth, and most of the open wounds were done with the Clay Buildup, Color Spray, Alpha 08. I’d build up some really lump skin, then smooth it down, and repeat with differing depth intensities. Then depending on the wound, I would add some bumpy or leathery skin alphas over it, and again, repeat.