Boa Hancock

The Pirate Empress Boa Hancock (海賊　女帝　ボア・ハンコック) is the only female member of the Shichibukai and was first mentioned by one of the Risky Brothers while he was talking about Mermaids to Sanji and Brook. She is the Snake Princess (蛇姫) of Amazon Lily and rules over it with her two younger Gorgon sisters, Boa Marigold and Boa Sandersonia.

Appearance
Compared to the abnormal appearance of her sisters, Hancock is a slender, tall woman with long hair dressed in a one-piece outfit. This beautiful appearance is noted by many throughout the world: to one of the Risky Brothers, her beauty is second only to that of the mermaids, while Marguerite claims she is the most beautiful woman in the world. Like every Shichibukai member, she has an animal theme: snake.

On her back is supposedly two Gorgon eyes, however this is simply a lie. While it is unknown what exactly is on her back, she seems most embarressed and shamed by it, enough to make anyone who sees it die.

Personality
Whether I kick a kitten... Tear off your ears... Even slaughter innocent people... The world will never cease to forgive my actions! Why, you ask? Why it is because I am... Beautiful!!! - Hancock's justifications for her actions.

Hancock is a selfish, pompous and spoiled person who is used to having her own way, although she does lie to the World Government about her agreement to wage war with Whitebeard simply to get them off her back temporarily. She is arrogant and cruel, justifying her actions with her apparently unmatched beauty and thinks that she can get away with anything because the world will forgive her. Her sister Sandersonia cheerfully calls her personality "Twisted". She has also proven that she will openly lie and her confidence leads her to never consider the consquences of her actions.

While a member of the Shichibukai, Hancock doesn't think much of the World Government and would rather keep her title but not go to war or perform certain duties if she had to, preferring to use her position to presumably nullify her former bounty and to protect her home from the government who sees all of the Kuja as pirates. She doesn't think twice about killing her so called Marine allies. She also apparently doesn't think much of the Kuja tribe either as she comments to Elder Nyon that she doesn't care if the island destroyed or not since everyone will forgive her because she is beautiful.

Her oddest trait seen so far is that when she looks down on people, she leans backwards so she faces the ceiling, apparently "looking down on people so much she's looking up."

Abilities and Powers
Ruling beside her sisters, Hancock has power over Amazon Lily and the rest of the Kuja women. As the Empress and Captain of the tribe, she is possibly the strongest Kuja warrior. Apart from her great beauty, Hancock has the ability to turn people into stone. This occurs when her hands form a heart shape, and beams are shot out of the shape. Anyone with "dirty thoughts" will be turned into stone. As demonstrated by Vice-admiral Momonga, the effects can be countered when the intended victim focuses their mind on other aspects such as pain, blocking out the "dirty" thoughts. Luffy also avoids the ability when his fear of death blocks out his feelings of lust from the attack after accidentally seeing the marking on Hancock's back.

This ability appears to be a Devil Fruit power as she uses the words "Mero Mero Merrow!" ("mero" is a sound effect of being in love), which is a typical way of using a Devil Fruit based attack. However, the contradictory story her fellow Kuja give is that she and her sisters killed a gorgon and were "cursed". The gorgon gave each sister a set of eyes on their backs. Whenever anyone sees the back of her and her sisters, they turn to stone. However, at the same time, Luffy was noted to have seen her back and not turned to stone, so it is unclear whether or not the curse is actually true. Luffy claims that he recognizes "that" on her back, and Hancock reacted annoyed to the fact that Luffy saw it. The fact that Hancock's a natural liar also belies the stories believability.

Past
At some unknown time she became a Shichibukai to make a treaty with the World Government, that would keep her island safe, since they considered all on the island for pirates. She and her sisters had also presumably killed a Gorgon and all three were cursed with eyes on their back that would petrify anyone who looked.

Straw Hat Seperation Arc
Hancock's first apperance was three days after Bartholomew Kuma had sent Monkey D. Luffy flying on her island (not to her knowledge). After sailing with her all-female crew, they met upon a Marine ship led by Vice Admiral Momonga, who told Hancock that the Shichibukai were being summoned to prepare for the upcoming war against Whitebeard, due to the execution of Portgas D. Ace a week from then. However, Hancock refused, stating that she would not obey the World Government, even though she fancied her Shichibukai position. When Momonga threatened to revoke Hancock's position if she didn't comply to the summoning, she came up with a make-believe story: The Marine crew would have turned into stone mysteriously.

She also demanded all the treasure on Momonga's ship (which the Marine rookies happily colplied to), and justified her selfish actions by claiming herself to be "beautiful", which everyone present (save for Momonga) vehemently agreed with. Then, she preformed a special move that mysteriously turned the Marines to stone, save for Momonga, who had stabbed his own hand to avoid the effects of her attack. As her crew sailed away, Momonga remarked that he would wait for two days, and if she didn't follow him, the treaty with the Kuja would be null and void. She arrogantly told him to "do as he pleased".

Upon returning to Amazon Lily, Hancock was greeted with plesantries though concerned that the warriors were not around, due to them chasing after a "monkey". She speaks with Elder Nyon (herself a former Kuja leader) about the danger that would befall Amazon Lily if she does not comply with the Government orders, but she remains arrogant and confident that both her power and beauty will allow her to get her way, throwing Nyon out of a window to prove she was right. When deciding to take a bath in privacy, she unexpectedly encounters Luffy, who falls down into her private area while looking for the person in charge, wanting to borrow a boat. He manages to see the symbols on her back and comments that he has seen them before. Attempting to use her powers, Luffy prevents them from working due to his fear of seeing her (or his simple mindedness preventing him from having 'dirty thoughts'), yet she still is able to lead the Kuja to capture him and take him to her arena.

In the combat area, Hancock shows no mercy to Luffy or anyone who tries to defend him, turning Marguerite, Sweet Pea and Aphelandra to stone for attempting to defend him after saving his life. At first attempting to use her panther Bacura to kill Luffy until he knocks it out with his power, she soon sends her younger sisters to attack him in the arena.

Trivia

 * Boa Hancock has several comparisons to the Greek character Medusa of the 3 Gorgon sisters. Medusa was said to be so ugly that those whom gazed upon her were turned to stone. Her ugly appearance was due to the jealousy of the Goddess Athena who discovered the beautiful Medusa with Poseidon in her temple in the midst of sexual intercourse. Athena had reshaped Medusa so that Medusa match the other gorgon sisters, one noted part of the transformation was to make Medusa's hair into snakes which links to the Kuja's theme of "snakes".
 * Her ability to seduce other men is a reference to Sirens, which would fit her abilities, as a Siren would seduce sailors and lure them to a watery doom.
 * She is the only female Shichibukai.
 * She is one of two women who have claimed to be the most beautiful in the world, the other being Alvida.