Nice texture with the shading! You get that really nice faint glow with the moonlight on the coarse scales, but then the ominous lighting gets another neat glow effect with the greens.
All in all, this dragon looks quite alive with how lovingly you got all the details down. Going over the details with your inkliner got all these crinkles and cracks on the spikes and scales, which really works well with the smoother details of the wings.
I'm also diggin' the colour scheme of the castle and the distant mountains, because castles/forts that are carved out of cliffsides are some of my favorite in real life.
Very impressive work all around! :D