This looks lovely~!
You have really clean and defined line work, and the solid coloring showcases that and allows the lines to breathe. I also like how the image is cropped! Great sense of action and the placement of Aqua balances out the composition nicely. I'm curious what materials you used? The texture of the brown belts and keyblade handle look super cool! Unsure if it was intentional or a happy accident.
Not sure what to criticize, there's a great balance between lines, composition, and striking colors that makes the image bold overall. Perhaps if you worked on implementing backgrounds - even simple ones - you could push the image further and create even more impact. If you're nervous about doing it traditionally, try your hand at experimenting in a graphics program digitally!