Very noice! Gives off a rather hunchbacky strong, overlordy supreme eveil dude kind of vibe.
His gauntlets are very tasteful.
Collarbone armor look decent, but seem a bit off. Perhaps try restructuring it so two large spikes (CCBS) of armor extend past the shoulders. Kinda like this
but better. Because drawing with a trackpad sucks
If you have the extra money to spend, perhaps try and acquire a pearl gold Kraakhan off of Bricklink, or get the black one painted somehow? The black one works, but I feel that the black is a minor accent color throughout the MOC, and not enough is present to balance out the large blob of black that is the mask. (I would recommend painting it; that way, the mask can be mostly gold and have accents of red and small spikes of black; this would make the colorscheme flow very smoothly)
Again, very nice work!