Boa Hancock is the ruler of Amazon Lily and the captain of the dangerous Kuja Pirates. She is a very complex character, who can at times prove to be a real handful.
Boa Hancock does not trust anyone except for her sisters, and the reason behind it is quite grim. As a kid, Boa and her sisters were kidnapped and sold to the Celestial Dragons.
The Celestial Dragons force-fed them devil fruits and used them for their entertainment. The sisters had no hope until Fisher Tiger broke them out of Marijoa along with the other slaves.After coming back to Amazon Lily, the three sisters got much stronger, and eventually, they ended up as the strongest members of the Kuja Pirates.
On their first ever voyage, the Kuja Pirates impressed the World Government, and their captain, Boa Hancock was offered the opportunity to join the Shichibukai, which she accepted as it would allow her to keep her island safe from any disturbance.Read more on gamerant.com