Well.... Lemme put it this way... Lucifer is NOT one you want to make angry... EVER......
As something a bit sketchy and unshaded, I think it works, especially as a good reference for his wings, sans coloring of course (though quite honestly I've never colored his wings accurately in the past either, just due to limitations I have in coloring mediums....)
Some constructive crit: His head seems... a taad large, and a bit too forward, sort of thorws off the perspective a bit. The legs are really good, and his pose looks awesome! 8D