Boa Sandersonia

Boa Sandersonia (ボア・サンダーソニア) is one of the three Gorgon sisters that rule over Amazon Lily. She and her sisters are called the Gorgon sisters for supposedly heroically slaying a monster called the Gorgon. She is the younger sister of Boa Hancock and the elder sister of Boa Marigold.

Appearance
Sandersonia is a large woman who resembles a snake. Her large head is shaped like that of a snake's and her tongue is forked. Like the rest of the Kuja, she dresses in very revealing clothing. She is usually seen accompanied with the large panther, Bacura, at her side instead of a snake like the other Kuja. On her back, covered by her cape and her long hair, is a mark of slavery branded on her by their previous Tenryuubito masters. It resembles a hoof mark and a sign that means that she is "less than human" since she was a slave. Her sisters share this mark as well on their backs.

Due to this shameful mark's meaning, Sandersonia and her sisters made their fellow Kuja believe that on their backs were a set of eyes she and her sisters received as part of a curse for slaying the Gorgon. They told them that these eyes turned anyone who sees them into stone. If any of the Kuja found out the truth, Sandersonia and her sisters would be forced to leave the island.

Personality
Sandersonia appears very fond of her sister Hancock as noted by the fact she laughed at her sister's "twisted" personality. While she appears to be living on the lie that her sisters and herself defeated a Gorgon to gain their curse, at the same time she hasn't actually told a lie herself unlike Hancock who is constantly lying. Sandersonia is the most emotional of the 3 sisters and highly emotional about their past, her crying had to be eased by her sister Marigold and drove her to collaspe onto the floor.

In battle Sandersonia is a playful warrior who teases and torments her victims before she crushes them.

Abilities and Powers
Ruling beside her sisters, Sandersonia has power over Amazon Lily and the rest of the Kuja women. Being a part of her sister's pirate crew, she is one of the elite Kuja warriors.

She possesses an ability similar to the Mantra of the Sky Island Priests. Using this, she is able to read an opponent's movements and avoid their attacks. The reaction of the Kuja warriors implies that this is a form of Haki. While she can do this, she being able to read an opponent's movement, although it is useless if said opponent is drastically faster than she is.

Devil Fruit
While she was a slave, Sandersonia was fed the Hebi Hebi no Mi, Model: Anaconda as part of some sick form of entertainment for her former Tenryuubito masters. This Devil Fruit allows her to turn into an anaconda. While these powers are Zoan Devil Fruit based, the Kuja of the island have been made to believe that Sandersonia's and Marigold's ability to turn into snakes is part of the curse the sisters made up. In their transformed forms, the other Kuja state that Sandersonia and Marigold can do a battle formation called Saragi Dance.

Shameful Past
Many years before the current storyline, when Sandersonia and her sisters were young, the three of them were captured by the slave traders while out on sea. They were sold off to some Tenryuubito and had their backs branded with the mark of slavery. As slaves of the Tenryuubito, they were horribly abused by their masters. As part of a cruel form of entertainment, Sandersonia and her sisters were fed Devil Fruits to amuse their masters. Living in this pitiful state, Sandersonia and her sisters could only think of dying. It was only until four years later, they were freed from this cruel life. A Fishman by the name of Fisher Tiger attacked Mariejois and freed the Fishmen slaves there. While Fisher Tiger hated humans, he also freed the human slaves which included Sandersonia and her sisters.

Not knowing how to return to Amazon Lily, Sandersonia and her sisters were fortunately able to return home thanks to a far from home Elder Nyon, who cared for the three girls like a mother. Thanks to having eaten the Devil Fruits while enslaved, Sandersonia and her sisters were able to come up with a story of them receiving a curse for slaying a monster called a Gorgon. This was all in order to cover the shameful marks on their backs from their fellow Kuja. Spreading this deception, they became Amazon Lily's rulers with her sister, Hancock, as the new Empress.

Accompanying her elder sister in a pirating campaign, Sandersonia and the rest Kuja pirates soon caught the attention of the World Government. Knowing how much power they had, the government signed a treaty with the Kuja and gave Sandersonia's sister, Hancock, the title of Shichibukai.

Secret Discovered and Battle against Luffy
On the way back to Amazon Lily after one of their pirating exploits, Sandersonia and the rest of the Kuja Pirates encountered the Marine Vice Admiral Momonga and his men anchored in the middle of the Calm Belt. Heeding his calls for Hancock to come before him, Sandersonia accompanied her sisters in greeting the Vice Admiral. Despite the Vice Admiral's demands that Sandersonia's sister comply with the compulsory Shichibukai meeting in which Hancock lied about attending, Sandersonia joined in her sister's continued refusal to help the World Government in such a critical. After her sister turned all of Momonga's men to stone, Sandersonia and the rest of the pirates took the stuff they stole from the Marines and returned to Amazon Lily.

After having arrived back, Sandersonia and her sister Marigold set forth to guarding their elder sister from any roaming eyes as Hancock took a bath. Unfortunately, as Sandersonia and Marigold were guarding, Luffy accidentally crashed through the roof of the bath they were guarding. Coming into the bath to see what happened, Sandersonia and Marigold found out that this man had saw what was on their sister's back while she was bathing. Realizing that this man had discovered their secret, the three sisters decided that Luffy had to die. However despite Sandersonia's eldest sister's attempts to turn Luffy to stone, Luffy was unaffected. Knowing that no one could be immune to her sister's beauty regardless of age and gender, Sandersonia guessed that Luffy's fear of death might be overwhelming any wicked desires. Though Sandersonia and her sisters couldn't eliminate Luffy then and there, the man was still captured.

With Luffy captured and brought to the arena of Amazon Lily, Sandersonia accompanied her sisters to see this man be executed along with the rest of their subjects. After her sister turned three Kuja warriors to stone for rescuing Luffy from some mushrooms, the panther that accompanied Sandersonia's side, Bacura, was sent to devour Luffy. However despite her pet's ferociousness, Luffy beat him with sheer brute strength. After this and Luffy's continuing apparent refusal to her eldest sister's charms, Sandersonia accompanied with Marigold decided to take things into their own hands. Facing Luffy, Sandersonia and her sister turned into half snake women and prepared to attack this man in a act the other Kuja called Saragi Dance.

As Sandersonia and her sister battled against Luffy, they decided to torment him by breaking Marguerite, one of the Kuja warriors who saved him, into pieces before his eyes. However just as Sandersonia was about to break Marguerite, Luffy shouted loudly at them to stop. Feeling the force from the Luffy's shout and seeing several Kuja warriors in the audience of the arena suddenly pass out, Sandersonia and her sisters realized that Luffy also possessed Haki whose caliber was on par with Hancock. Stunned by this revelation, Sandersonia and her sister Marigold watched as Luffy decided to fight them more seriously.

Having seen that their opponent was no ordinary man, Sandersonia and Marigold decided to fight against Luffy more seriously as well. Unfortunately, upon Luffy activating Gear Second, he proved too much for Sandersonia and her sister. In the middle of the fray, Sandersonia accidentally got caught on fire by her sister's technique. With her tail also tied to her sister's by Luffy, Sandersonia almost fell down to spiked pit around the arena while on fire. Though the fire was put out and she was able to reach the stands to prevent her from falling, the fire unfortunately burned all of her top clothing, including the cape that covered her back. With the cape burned, her long hair unable to cover her back due to her position, and the smoke clearing, Sandersonia and her sisters' secret was about to be exposed. However before anyone of the Kuja in the audience could see her back, Luffy covered Sandersonia. Wondering what he was doing, Luffy explained to Sandersonia that despite the fact that she and her sisters were trying to kill him, he had no intention of killing them nor did he had the intention of allowing their deep secret being revealed. With Sandersonia's back covered, her sister, Hancock, ordered everyone to leave the arena.

Current Events (spoilers)
With their secret safe, Sandersonia's sister, Hancock, decided to reward Luffy for concealing it. However, Sandersonia's sister told that Luffy he could ask for one request, a ship or to turn Marguerite and the others back to normal. Much to Sandersonia and her sisters' surprise, Luffy asked for the latter. After the three Kuja warriors were reverted back to normal, Sandersonia and her sisters decided to discuss what Luffy saw on her elder sisters' back. Learning that Luffy mistook the symbol for the one on a fishman friend of his named Hatchan, they soon also learned from Elder Nyon that this man was Monkey D. Luffy, a pirate whose act of defiance against a Tenryuubito was reported in the news. Discovering about this, Sandersonia's sister decided to explain things to Luffy despite the horrible memories they held. Having explained things to Luffy, Sandersonia and her sisters learned that Luffy completely hated the Tenryuubito for their crimes. With this, Sandersonia's elder sister decided to lend Luffy their ship.

With Sandersonia's sister deciding to help Luffy, the pirate was soon accepted within the community of the island. However despite the festivities celebrated around Luffy, a more important matter soon arose that caught Sandersonia's attention. Her elder started acting strange. Not knowing what was happening to her, Sandersonia and everyone else who tended to Hancock's side thought she had contracted a disease. When news reached Elder Nyon, the old woman apparently confirmed their suspicions and told them that it was something the previous Empresses of Amazon Lily had died of. As all this was happening, Elder Nyon told Sandersonia's sister that Luffy wanted to talk to her. Despite Hancock's condition, Sandersonia's sister decided to talk to Luffy alone.

Hiding alongside her younger sister so they can eavesdrop, Sandersonia learned of what Luffy wanted. It turned out that Ace, the one was to be executed by the World Government, was actually Luffy's older brother. The pirate asked Hancock to answer the compulsory Shichibukai call so he could join her and sneak into Impel Down were Ace was being held before his execution. Hearing this request, Sandersonia and Marigold were deeply outraged of what Luffy was asking. Knowing how much emotional pain it was to return to the cursed "Holy Land", the two of them were expecting their sister to turn Luffy into stone for asking such a thing. However much to their surprise, their sister accepted Luffy's request while blushing. It was then that Elder Nyon revealed to them that the disease that their sister had contracted was actually "love sickness".

With her sister's decision, Sandersonia and the rest of the Kuja Pirates saw Boa Hancock off to Momonga's ship along with her snake and Luffy hiding in her coat. With their sister going to Mariejois, Sandersonia and Marigold promised Hancock that they'll take care of Amazon Lily in her stead.

Trivia

 * Her name comes from the flower Sandersonia.
 * While Sandersonia and her sisters' title, the Gorgon Sisters, comes from supposedly slaying a monster with the same name, their concept is loosely based on the three actual mythological Gorgon sisters which includes the famous Medusa. Sandersonia is also able to convert her hair into snake-like, snake hair was another gorgon trait.