Hiding behind crazy stunts and extreme lifestyles to prove something to both himself and everyone else, even if they don't know what he's trying to prove. Not liking responsabilities and social chains, he often flukes the rules set upon him. Being surrounded by people who take life far too seriously, he is often a refreshing touch to any conversation as he doesn't take it seriously.
Beneath his mask, though, Jax is quite insecure and scared, slightly believing himself weak and frail in comparison with others. He wants a happy life, with friends, family, and a healthy body and doesn't believe he'll be able to do this if he opens up about his illness.