BlackWing has been one of my favourite characters of mine for forever. Since his inception, which was as a bad guy, the antagonist, and the opposite to my main protagonist, Jet. His appearance was of a dark and evil looking pegasus, malnourished and gaunt, twisted into hatred and loneliness. Jet becomes the subject of his anger after an altercation, because BW wasn't used to being bested at anything (it's very easy to hurt his pride).
After a year of pursuit and trying to exact his revenge, Jet winds up saving his life and ultimately forgiving BlackWing for his wrong doings. BW joins Jet's crew/herd, and after a roller-coaster of ups and downs, they're now best of friends and herd-brothers. BW's whole appearance changes, and despite being called 'fat' sometimes, he's clearly more balanced and contented. He now channels his anger into training in the martial arts, building cars and tinkering with other sci-fi machinery in the world.

A library of other pictures of him can be found at these links:
http://s114.photobucket.com/user/jet3270/library/blackwing/
http://jet3270.deviantart.com/favourites/2005878
All are SFW with some toplessness. More explicit rudey nudey info available on request.