The Heterochromia iridum, the soft blue light on the green eye side (If it was on the blue eye side it wouldn't stand out as much). Your painting is perfect. If someone told me this was Mary Ryden, I would be believe them.
And again you managed to do some amazing piece of art I like the effect the shading and the soft blue hilight give to the picture. The armor she is wearing looks adorable ^^ And she looks cute (like all of your other figures )