Gorgon Sisters

The Gorgon Sisters are the three sisters of the Boa family. They rule over the entire Kuja tribe and the Kuja Pirates.

Members

 * Boa Hancock: Eldest sister, Empress and Captain of the Kuja, possesses the Mero Mero no Mi and Haoushoku Haki.
 * Boa Sandersonia: Middle sister, second-in-command of the Kuja, possesses the Hebi Hebi no Mi, Model: Anaconda and Haki.
 * Boa Marigold: Youngest sister, second-in-command of the Kuja, possesses the Hebi Hebi no Mi, Model: King Cobra and Haki.

Legend of the Gorgon Monster
They received their nicknames due to their supposed heroic act of slaying a monster called "Gorgon". As punishment, the Gorgon has cursed the three of sisters with a pair of eyes on each of their backs, which would petrify anyone who set eyes on them. Also, as part of the curse, Hancock has the ability to petrify anyone that shows lust to her, while Sandersonia and Marigold can transform into human-snake hybrids at will.

Shameful Truth
In truth, what the three sisters bear on their back are the "Hoof of the Soaring Dragon", which is a symbol of them being slaves to the World Nobles, and the mark that is burnt deep into their flesh will forever mark them to be less than humans. Their powers of their "curse" that they received from the Gorgon were actually Devil Fruits fed to them as a form of cruel entertainment for their masters.

For four years, the sisters were tortured and humiliated day and night, wishing for death. Like many people, slaves or not, they did not dare defy the World Nobles, for the fear of facing a Marine Admiral. Then, when Fisher Tiger attacked Mariejois and freed every slave there, the Gorgon Sisters were indebted to him, of which they could never repay.

Even though freed, the sisters were unable to return home, until they met Elder Nyon, former empress of the Kuja tribe. In order to hide their shameful past to the rest of the tribe, they used the Kuja's lack of knowledge about the outside world (especially about Devil Fruits) and concocted a story about the Gorgon. As such, when any of the three sisters were to take a bath, the rest of the tribe were to evacuate the area, in fear of being petrified. However, this was to ensure that the Hoof of the Soaring Dragon would not be seen.

Rulers of the Women Tribe
As Hancock became the new empress of the tribe, with her sisters as her seconds-in-command, they formed the Kuja Pirates, and Hancock became a member of the Shichibukai, in order to obtain a treaty to protect the rest of her clan from any more intruding outsiders from entering their homeland, Amazon Lily.

However, despite going that far to protect her tribe, four years of cruel torture and humiliation has ruined Hancock's innocence, and she became uncaring to anyone but her sisters. In fact, she was willing to forfeit her position as Shichibukai and allow the treaty to be nullified, as she despised the World Government for being responsible for her terrible past.

The Gorgon Sisters would also hold hatred towards men, as the first man they ever saw in their lives was the one who branded them with the Hoof of the Soaring Dragon. They believe men are all selfish and cruel based on that experience, and would hold that believe for years.

A Renewal Thought of Men
Years later, when Monkey D. Luffy was sent to Amazon Lily by Bartholomew Kuma for attacking the World Nobles, Luffy accidentally saw the mark on Hancock's back, prompting the Gorgon Sisters to kill him. However, after Luffy showed selflessness by protecting their backs from being shown to the rest of the tribe, as well as willing to forfeit his own chance to leave the island to save some petrified Kuja members, the Gorgon Sisters has a renewed thought towards men.

When hearing that Luffy has attacked the World Nobles, Hancock has mellowed out, allowing her soft and sensitive side to resurface, and that she even fallen for Luffy. She was willing to help him save his brother, Portgas D. Ace, who was nearing a public execution, even if it means for her to return to the World Government that haunted her for years.