Nice one! Nice colouring! But Dosu doesn't look scary enough unfortunately... lol! I'm sorry to say that. Even though they might be yaoi-pals and all he should still look a little bit more intimidating... He's the man in the relationship after all!
Could have something to do with the arm and it could have something to do with the amount of skin that we are able to see. In the sketch it would be black and white so one would get the impression there is a lot less skin: we might not be able to tell the difference until it is coloured!