Sven Sauer and Igor Posavec has a step-by-step of their “Dead Angels” graphic up on CGArena. They used 3D Studio Max for the base modeling with ZBrush for the detailing, and it’s a great collaboration between a classical artist and digital modeler.
The Illochim (Herbrew: Engel) was here represented as an ancient race out of the depths of space. To create a different view on the misinterpreted creatures, Antoan Simic started first with the rough sketches of the chimera that gave birth to the legends of angels and dragons alike.