One Piece: Nefertari Vivi

Nefertari Vivi first appears as an antagonist as the main characters reach the Grand Line, as a member of Baroque Works, a criminal organization that was behind several scandals in the country of Alabasta. It is revealed that Vivi is actually the princess of Alabasta, but infiltrated Baroque Works as Miss Wednesday to find the identity of the leader, who turns out to be the Shichibukai member Sir Crocodile. With help from the Straw Hat Crew, she was able to reveal the truth to her people, ending several uprisings and stopping battles that would have forever ruined the nation.