This image was inspired by 'Song of the Wayland' by Anslem Kiefer, a dark painting with the green greys you see here. It also has a metal wing - hence the angel.
I sketched him direct to 3D in Curvy 3D ( www.curvy3d.com ), making up the design as I modelled him. It only took a few minutes to sculpt the basic shapes - then most of my time was spent painting on details in 3D.
The cyan fog was added in Painter afterwards.