So, the base colors of the OC are really similar to the sort of white/off white background, they blend too deeply and it makes it hard to decipher the lineart.
The orange feathers and detailing in general really pops, excellent job there.
The white smog-fog is very nebulous, I'm not sure if it's a cloud or a portal or what? If you want, you could have it be emanating from the creature, or change the background colors so it looks like a sunset.
And, then, the style of the city is very cute, but jarring against the detailing of the OC , it almost looks clumsily done beside it. Not because it is, but because of the detailing present.