Mmmmmm, I'm not sure. That's your call. c; If you want it, then keep it! If you're fine with parting with it, then go ahead and sell it. Either works. ;3 I'd definitely be interested in buying him/her if you do decide to sell the design, though. ^^
I really love the dark atmosphere and the characters intense gaze - the eyes look like they're burning through your soul. The colours are nice and dark, and the whole glow that resonates from the white parts make it seem ethereal, it's such a cool ensemble. I'm loving this iamge! Is there a story behind this character?