The vibrant colors on this are just gorgeous, and the switch from bright to... I don't know how to describe it, but using the cool colors alongside the warm ones at the divine instrument looks really nice here. Amaterasu herself is really great to look at. I'm especially loving the way you applied her markings.
The spirals in the background I'm not so sure about. The coloration works well, but the upper right feels a bit empty in comparison to the rest of the image, but adding another spiral may make it too busy. It just feels like something else could be done there.
All in all, this is really eye-catching and beautiful.
At first glance it is a nice job and well done. Going to notice the details and then, I think the technique used is not bad especially in the combination of colors that meet enough of those original Okami. Some parts are not accurate, but obviously not'll look after that. I really appreciate the pose, even if the background could have been slightly more detail. The red spirals, for example, it might be better to put them at different distances, not on the same axis. Finally, I would have opted for ... Um .. Cherry blossoms, typical of Okami, or other decorations more "material" not geometric. Anyway nothing to say, beautiful, original in the pose and good impact.