Crocodile

Crocodile is a character in the world of One Piece. Crocodile was once a Shichibukai but was stripped of his title after attempting to take control of the desert kingdom, Arabasta.

Mysterious Past
Noone knows exactly where Crocodile came from, in every image of him, he has a strange scar across his entire face, all stitched up, as well as a hook on his left hand. It is known, however, that he wears the hook for utility, and not because he is missing a hand. Crocodile was the Shichibukai with the lowest bounty at the time, and was likely the only one known to have a bounty of less than 100 million Belly. It was stated by Crocodile himself that he was not much different from Luffy once, and also wanted to become the Pirate King and have adventures.

Baroque Works: Early Days
Crocodile secretly started a mysterious group, called Baroque Works. Being careful not to attract too much attention to himself, he gathered some of the best bounty hunters in the world, and gave them codenames based on power. His plan the whole time was to capture Arabasta and read the Poneglyph there to find the ancient weapon, Pluton, and gain whats he desires, Military Power.

It is known that he found Nico Robin at the age of 16, and made a deal with her. He'll protect her and give her a home, and she can be his partner. In return Robin will read the Poneglyph and find the location of Pluton.

Modern Baroque Works
After 10 years or more of planning, all the Baroque Works agents finally met Sir Crocodile, and were given their final assignments. Crocodile, fighting and defeating Luffy twice, nearly killing him each time, finally beleive himself to be rid of Luffy. Nico Robin and Crocodile were brought to the Poneglyph Chamber in the Royal Mausoleum Grounds by the king, Cobra, who was forced to lead them there. Crocodile is bey=trayed by Robin who reads off history she knows, of both Arabasta and other points in the world. Luffy caught up, andfinally defeated Sir Crocodile, with a super version of his Gattling Gun, Gomu Gomu No Storm! With that came the end of Baroque Works, and Crocodile.

The Ex-Shichibukai
Tashigi, going by her own justice as Captain Smoker ordered, arrested Sir Crocodile, and by the Naval Justice Clause, was stripped of all titles and permissions granted by the Marines and the World Govenrment. He was taken to a prison, and after all the othe rmembers were broken out, he refused to go. Crocodile and the rest of Baroque Works are currently being transferred to Impel Down. Many theories surfaced about Crocodile possibly helping the Straw Hats escape from Enies Lobby, but nothing of the sort ever happened.

Trivia

 * In a Cover Story Mini-Arc, Crocodile was originally drawn with both hands, and no hook. This was corrected for the release of the Volume and is now published with the hook correctly place don his left hand.
 * Crocodile is the only known character so far to have almost totally master his Logia Devil's Fruit, and is able to turn to Sand as a reaction to touch, effectively giving the appearance that he automatically turns to Sand once he is hit, which is a common misconception about Logia Users.