Who is Little Bee/Udo from Little Bee: A Novel and what is their importance?

Little Bee is a Nigerian girl whose village was overrun by men paid by the oil companies to run the people off their land. All the men were killed as the women fled into the jungles. The women were killed as well, run down in the jungle. Little Bee and her sister escaped, but the men continued to search for them for days, finally finding them on a beach. A white couple was on the beach and tried to intervene, but the man could not bring himself to pay the price the oil man wanted. Little Bee's sister was killed, but she survived to escape to Britain on a tea ship.