Ai Enma is a fictional character from the anime series 'One Piece'. She is known as the Hell Girl, a mysterious and ethereal figure who appears to exact revenge on behalf of those who summon her. Despite her haunting presence, Ai is a complex character with a tragic past, and her journey throughout the series unveils her struggles with the curse she bears. Her role is crucial as she embodies the themes of vengeance and redemption, making significant impacts on the lives of those she encounters.