The one I saw in your gallery waqs pretty nice, though if I may make a suggestion; try giving Kimimaro horns. It would add to his tortured look I think, how willing he is to go to serve Orochimaru even at the cost of his own humanity.
i was thinking about making him look more big, more powerful. Maybe add a little of the evilseal-look, and waiting in a hideout like the one of madara, but with more horns