Well he is sad and lonely, short tempered,He gets depressed a lot and he is very stubborn. His special talent is defense.
His brother died in the episode 'A Canterlot Wedding' and is now ,after trying to attack chrysalis,on the run from the changeling hive/kingdom for treason.
He wonders Equestria, refusing that his brother is dead, trying to find a way to bring him back.
Is this enough? If not tell me and ill get back to it in the morning(Its midnight here and it's been a long day : P