Trafalgar D. Water Law

Trafalgar Law is the captain of the Heart pirates. He is one of eleven pirates who have been referred to as "The Eleven Supernovas" on Sabaody Archipelago whose bounties are higher than  100,000,000 when the Straw Hats arrive in the place.

Appearance
Law wears a shirt with a smilie symbol on it, which is similar to the flag of Donquixote Doflamingo. He has many tatoos on his arms, as well as a pair of small earings on his right ear.

Personality
That's the guy from North Blue, with the two-hundred-million bounty... Trafalgar Law... I've heard rumours about him, and they weren't pleasant. His manners aren't too good either...-Kid about Law

Law is an extremely laid-back character, who is nearly always seen smiling (although not with a huge grin, like fellow Supernova Urouge). He also has a more reckless attitude when faced against other pirates that the World Government has labeled as a higher threat: For example, he casually asked X. Drake how many people he had slain in his very first appearance, and had no qualms about flipping his middle finger at Eustass Kid, the most wanted Supernova on the Archipelago (even smiling defiantly when doing so). However, he hates being ordered around, as evidenced of his frown and following reply when Kid told him and Monkey D. Luffy to stay back as he would hold off the attacking Marines. He is also unfailingly polite, usually referring to others as "Mr".

Abilities and Powers
Law is a doctor whose skills have earned him the nickname of "Surgeon of Death". As for his weapon, he carries a Nodachi with a scabbard decorated with crosses from the opening to the bottom. With this sword, Law can swiftly cut objects from a distance; though it is not clear whether or not this is only applicable when both him and his target are within the range of the radius generated by his Devil Fruit powers. He, along with his crew (save for one who nearly collapsed) proved resistant to Rayleigh's burst of spirit energy that took out almost all in the Auction house

During an assault on the Human Auctioning House, Law revealed himself as holding a Devil Fruit power. His ability allowed him to create a spherical territory (not necessarily centered on his location but wide enough to cover several meters) where he can replace and switch any objects from their respective locations within it instantly at will, but presumably only if the two objects to be displaced are roughly of equal size. Using this ability, Law was able to make it seem like he sliced the head off a Marine, only to replace it with a cannonball that was being fired towards him. The Marine's head on the other hand, remained alive as it flew into Law's hand and could see the cannonball floating and exploding over his body. With the exception of Trafalgar himself, anything caught within the territory generated by his power also seems to lose momentum (similar to the efects of Foxy's Noro Noro Beam), causing it to move very slowly, as was seen at the cannonball fired at Law's direction which moved at a noticeably delayed pace after getting within the reach of Law's power. In fact, so slow that by the time Law switches it with the decapitated marine's head, the pirate captain was able to catch the disembodied head with his free hand; the cannonball, however, reverted to normal speed after this was done. The identity of the ability remains unknown at this time.

History
Like the other Supernovas, he was first shown having arrived at the Archipelago with his crew before heading for the New World. He was the final Supernova to be introduced, seen sitting on a crate as X Drake, another Supernova, passed by after having broken up a fight between Urouge and Killer, before he asked how many people Drake had slain. Later, Eustass Kid observed him in the Auction House on Grove 1, where he revealed that what he had heard about Law was not very pleasant, and as he said that Law was lacking manners, Law replied with flipping the middle finger. As the auctioning continued, Law only observed in boredom.

After Monkey D. Luffy attacked one of the World Nobles, he was seen smiling at the reckless action that his fellow Supernova had preformed. A short while after, Law revealed to Luffy that the auction house was surrounded by Marines, since the Archipelago was so close to Marine Headquarters (although Luffy was more interested in the bear who was with Law). Later, after Silvers Rayleigh had knocked out the majority of the soldiers standing in the pirates way, he was seen still standing, along with his crew, the Straw-Hats, Kid, Killer, and their crew as well. After the Straw-Hats and Rayleigh prepared to leave the Auction House before the admiral would show up, Kid told Luffy and Law to stay back as he would hold off the Marine grunts, much to both Law's and Luffy's annoyance (Law even went as far as to tell Kid that he would finish him off too if he ordered him around again). Then, the trio demonstrated their Devil Fruit powers to hold off the Marines, Law utilizing a field where he replaced a grunts head with a cannon ball fired at him.

Trivia

 * Trafalgar's name probably derives from the famous "Battle of Trafalgar" between the British Royal Navy and the combined force of the French and Spanish Navies in 1805.