Pokemon XY What CarnieVorex said and
Pay attention to your color a little more:
Adding a lighter tint (pulled from the sky's blue) to the Altaria in the back will show depth. Adding a little bit of a rim lighting on Xerneas's silhouette from the light source would make him (it?) less like a black blob...
I'd even say replace the black in your image with the darkest shade from your nearest environmental hue. For Xerneas, it'd be that bluish-green in the cliff.
Oh and I must complement you on your lovely and honorable addition of the rare Floating Tree.
Kids these days...they just don't know how to appreciate such a marvelous works of nature
Lolo Jump 
