Bartholomew Kuma is a former member of the Revolutionary army and current member of the shichibukai in the popular manga and anime series, One Piece.
Kuma was once a feared pirate who was commonly called "Kuma the Tyrant".
It is unknown why Kuma joined the revolutionaries, and by extension, why he would later align himself with the World Government. Apparently, the revolutionary leader, Monkey D. Dragon, knows the truth behind Kuma's actions, and offered to explain them to Emporio Ivankov.
Kuma became the model for Dr. Vegapunk to create human weapons known as Pacifista. Kuma's own body was slowly modified to become a cyborg, and eventually, lost his own conscious.
Kuma is a very large man of over 22 feet tall. His appearance is modeled after bears. (As can be deducted from his name, in which Kuma means bear in Japanese) For some reason, he is always seen carrying a copy of the bible.
As a human, Kuma did not appear to express a great deal of emotion. Kuma has shown on multiple occasions that while he is technically affiliated with the World Government, he doesn't necessarily agree with many of their ideals. (Which would seem obvious, as he was undercover as a Revolutionary)
After his latest modification, Kuma lost all of his free will and conscious. At this point, Kuma acts solely on what he's programmed to do.
Powers and abilities
Kuma is the current user of the Nikyu Nikyu no Mi (Paw Paw Fruit) which allows the user to repel anything that touches the paws. Kuma uses this ability to launch almost anything (including people) at incredibly fast speeds.
He is also able to repel air and condense it into a tiny ball, which he then launches and causes the compressed air to decompress into a giant explosion.
Another interesting use of his power is the ability to repel someones pain. Using his paw, he was able to pull all of Luffy's physical pain into a giant ball, which can then be transferred on to another person.
He used his ability to seperate Monkey D Luffy and his entire crew by sending them all across the Grand Line.