First part of the image I'm currently working on. The characters, Drayk, Zaryn, and Janarr belong to Drayk.

With a light gray background in place, I use 50% gray to fill the character, then I set a soft round brush to 10% opacity in Photoshop, and use white and black to develop the shadows and highlights.

This is as far as I'm taking this for now. I'll keep the updates going as I progress.