The atmosphere is quite nice and I love the colours you've added to his skin tone -the pinks and purples add a very nice contrast to the yellow highlights along his face, and give him a slightly sinister look around the eyes while paired with the green glow. I do think there could be a little more saturation to some of the shadows, as in certain places it looks just a wee bit washed out. Your anatomy is just about spot on as usual, though the cropping does make his arm look a little odd - I feel like we should be able to see a little more of his right forearm rather than just his bicep in the background and his hand. The rest of the colouring looks very solid and I love the straight black hair. The only other thing I would mention is that the tattoo texture on his arm looks a bit flat, and doesn't seem to curve along with his muscles - this can often be fixed by fiddling with the warp tool in photoshop if necessary.
All in all, this is yet another beautiful portrait! I love his hair, and your linework is completely lovely. ♥