Haibane
The ashfeather (灰羽, haibane) is a type of creature possessing wings and a halo, the significance of which has been forgotten. Their small wings do not possess enough area or power to allow the haibane to fly using them. The halo is forged by the Ashfeather Council (灰羽連盟, Haibane Renmei) and given to freshly emerged haibane. Glie has apparently been fashioned for their existence, but not according to it, since the city is operated primarily by humans. Haibane are at both the top and bottom of the social order in Glie, with the Ashfeather Council at the top, and the rest of the haibane at the bottom. Only the Communicator (話師, Washi) of the Ashfeather Council can regulate the trade with the Toga (トーガ, Tooga) outside the wall, using a secret sign language (unofficially Toganese トーガ言語 (Toogagengo) in FHD Remix)
Haibane appear to be resurrected or reincarnated beings from a previous life, the cocoon dream being a final or significant, possibly metaphorical memory from that past life (Of the two that we see, Rakka has in it a crow; all but certainly this creature, in Rakka's past life, would have been of the same sentient species as Rakka's precursor. In Reki's cocoon dream, it is apparent that her precursor was struck by some sort of large vehicle that runs on iron rails, each of which may represent something that it does not appear to be in the cocoon dream, for example, an aircraft and runway.)
Haibane are named for their cocoon dreams, for example, Falling, (落下, Rakka), Small Stone (瓦礫, Reki), Fluffy (綿毛, Menmo), Gloomy (暗い, Kurai), Empty Air, (空, Kuu) and Battle, (闘い, Tatakai).