I really like the use of overall shape here. The general shape has that pleasing sleek form tha the horns reinforce, ye there are a lot of triangles that give interest in the form of a secondary shape and are just plain cool. I really like that you have added a spiked collar, which suits Firael. The grungy, rather ruinous background have a 'street' and 'post-apocalyptic' look that suits the subject and overall mood, too... majorly by its urprisingly realistic look, contrasting wi the sketchbook style that Firael has.

Overall, Firael is o cool-ooking there!