One-Winged Shiroi, Kou and Buttons by @sheianto (Sheila Antonio)

I was hoping to add this lil side story into the manga but I guess it's too much. Oh well, here's a summary (please refer to the previous drawing for info).

The Shiroi is comprised of 5 special humans personally selected by Tsubasa (during his time, he was the only angel able to walk among and protect humans). He plucked a few of his feathers from his wings and embedded it into these humans, who instantly became angels. From then, they continued this method of careful selection for future Shiroi. A special exception was made whenever a Shiroi starts a family of their own, so their children were born as angels.

Kou is a descedant of the Shiroi but for some reason was born with one wing. Because of this, Kou sets off a lonely journey to elarn more about the Shiroi and his family lineage (He is actually adopted). He accompanies Buttons and they both help each other on their personal journey.