My fursona is sort of a shadowy demonic corvid guy and I wanted to give him more lore, so I drew some concepts of other demon crows and their anatomic variations, I might call them corvians.

The rules I've made for the species so far is that they can have bird talons, or just pointy feet. Wings can be on their back or their arms, those who have wings on their backs can retract them when they need to fit in certain spaces, bird tails, and their hair must have a crest or tufts to assemble bird feathers. Since they are demons they're kind of shadow figures with a not so tangible body so they can leave little trails of smoke and also hide their facial expressions