"Pirate Empress" Boa Hancock is the captain of the Kuja Pirates and was the only female Warlord of the Sea before the organization's disbandment. She is the current empress, known as the "Snake Princess", of Amazon Lily and rules over the Kuja tribe with her two younger sisters, Boa Sandersonia and Boa Marigold.
Kidnapped by the World Nobles as a child along with her sisters, she was enslaved and tortured for years; during this time she was force-fed the Mero Mero no Mi, which gives her the ability to turn both living and non-living things into stone. She and her sisters escaped from Mary Geoise during a mass breakout instigated by Fisher Tiger. She was returned to her home with the help of Gloriosa, Silvers Rayleigh and Shakuyaku, where she would eventually become the island's empress, as well as one of the Seven Warlords.
Though initially antagonistic towards Monkey D. Luffy, his selfless actions and animosity towards the Celestial Dragons caused her to befriend, and eventually fall in love, with him. She went on to serve as one of Luffy's most stalwart allies, helping him infiltrate Impel Down, siding with him in the Summit War of Marineford, providing him a location to train on for two years, and then helping him reunite with his crew and supporting him from afar.
While employed within the Seven Warlords, she turned against the World Government on a number of occasions to support Luffy, though she was able to retain her title by feigning innocence. However, the Warlords were officially abolished after the most recent Levely, causing her to lose her status and became one of the world's most wanted criminals. Vegapunk was able to clone Hancock as one of the Seraphim, S-Snake, to replace the Warlords.
She initially serves as the main antagonist of the Amazon Lily Arc, before becoming a major ally for the rest of the Summit War Saga, as well as the Return to Sabaody Arc. She also acts as an ally of Luffy during the 3D2Y special, the Cidre Guild filler Arc, and the movie One Piece: Stampede.
She first gained a bounty of 80,000,000 due to her being a captain of the Kuja Pirates before it was frozen after she joined the Seven Warlords. However, after the abolition of the Seven Warlords, Hancock's bounty was reinstated and raised to 1,659,000,000.
Hancock ate the Mero Mero no Mi, a Paramecia-type Devil Fruit that allows her petrify people into stone statues, so long as they feel attraction for her. She can completely turn people to stone by hitting them with any of a variety of heart-shaped long-range attacks, as well as partially transform them by striking them physically, only petrifying the area she struck.
During her time as a slave, Hancock and her sisters were force fed Devil Fruits by their Celestial Dragon owners as a form of sick entertainment.
Thanks to Hancock's unparalleled beauty and charm, very few people (male and female alike) can resist her powers, allowing her to petrify whole crews with no difficulties. Even extremely powerful people are vulnerable to her power if they find Hancock attractive.
She can also return her victims to normal if she chooses by blowing a kiss. Only she can undo the effects of her power, if she dies, the next user of the Mero Mero no Mi would not be able to free her victims.
A would-be victim is immune to Hancock's power if they block out their "dirty thoughts", such as by feeling strong fear or pain, or if they are simply not attracted to her, such as a blind man not knowing how beautiful she is.
Haoshoku Haki
According to Sandersonia and herself, Hancock possesses the ability to use Haoshoku Haki. But she has not yet showcased her usage of it in the manga.
Busoshoku Haki
Hancock is a highly skilled user of Busoshoku Haki, able to combine her kicks with this type of Haki to bypass a Logia's intangible defenses.
Kenbunshoku Haki
Hancock possesses the ability to use Kenbunshoku Haki. At the end of the Summit War of Marineford, she was able to detect that Luffy and the Heart Pirates were still alive and had escaped, despite the Admirals' attempts to sink them.
Hancock carries with her an extra-large white snake with red marks on its body named Salome, that wears a skull with blue hair jutting out of the back and a constant smile. However, aside from using it as a throne as well as to elevate herself above the battle, changing itself into a spiral shape while doing so, she has yet to use it in actual combat.
Salome has the ability to track and sense things on the ocean floor, which was shown when it was able to sense Whitebeard's earthquake before it arrived and when it helped Hancock follow the Heart Pirates' submarine.