The Miracle And The Sleeper
Sorry, no real ideas for feats or skills... however, you might be interested in character development. I suggest you look in twin psychology and especially the reference to what I've heard is called the Miracle and the Sleeper. The theory suggest that one of the two twin is always the miracle and the other the sleeper. One is good in everything, the other merely a shadow of the other.
Think of Romulus and Remus (founders of Rome according to the legend), although Cameron and Raistling are quite similar...
Even though I did study the psychology, I came upon that term (The Miracle and The Sleeper) through a song by Dream Theater. Metropolis part I, about the story of two brothers, founding a city, each one fighting for the love they have for it and one of the two killing his twin in the process. Metropolis part II (entire concept album), about a guy who has memories of a girl being killed around 80 years ago by her future husband (judge, successful, miracle) when he learns that she (rome ?) 's in love with his brother (bum, no future, sleeper)...
Might be interesting for your character development...
chris