What kind of character is Dally, beyond his physical appearance?

Dally's real name is Dallas Winston, and he is the toughest member of the greaser gang. His eyes were blue, blazing ice, cold with a hatred of the whole world." He is a jockey, and surprisingly doesn't fix races; it's "the only thing Dally did honestly." Although he is only seventeen years old, "the fight for self-preservation had hardened him beyond caring."