Angel Wing was born with an abnormality in the final joint in his wings causing them to be turned outwards (a condition called "angel wing" in ducks and swans and such irl). As a result, he's completely flightless, which can be a lot to deal with when your mom is a wonderbolt. He really looks up to Rainbow Dash and sorta beats himself up for not being able to do what she can. Lucky, his other mom, Bubbles, is pretty familiar with living with a disability, and between her and his aunt Scootaloo, he ends up coming to terms with loving himself WITH his disabilities.
He comes across very stoic and sorta intimidating, but he's an absolute sweet heart who genuinely cares so deeply for everyone he meets. He really looks up to the way his mom and the rest of the mane six kept the world at peace and protected and wants to do that on a smaller scale. His focus is more on the community, trying to build it up and support others where he can.
Also the streak of hair is 100% self dyed bc he wanted to look like Rainbow Dash LOL