Sawyer

Pre-Crash: His birth name is James Ford. When he was young, his father killed his mother and then himself after the couple was conned by a man named Sawyer. When he grew up, Sawyer took on the name of the con man and learned to con.
One of his cons, Cassidy, figured out what he was doing and asked to be a part of it. The two conned together for awhile until he conned her. He ended up in prison, where Cassidy visited him to tell him he has a daughter.
Sawyer made a deal with the warden and was let out of prison. He anonymously sent his reward money to Cassidy's daughter.
He got news of where the real Sawyer was and went to Australia to kill him. After shooting the man, Sawyer realized that he had been conned and the man he shot was not the real Sawyer.
Island: Sawyer wants everyone to believe he is a jerk. He steals and hordes whatever he can.
Sawyer cons Jack and Locke and ends up with control of the guns. He and Kate seem to have a love/hate relationship.
Sawyer is captured by the Others, along with Jack and Kate. Sawyer and Kate are kept in cages. Kate climbs out of her cage and the two sleep together.
Strong Relationships: None
Rocky Relationships: Kate, Jack