Riro  

The alien responsible for Earth's attacks has been revealed as the youngest among them. Over 100,000 years ago, Riro arrived on Earth and gave a pair of glasses to a young primitive girl. These glasses were instrumental in shaping human civilization. Eventually, Riro's glasses landed in Yuuki's possession. Without her glasses, Riro lost all emotions except for the desire to destroy. However, she was redeemed when Yuuki returned her glasses. By the end of the series, Riro and Yuuki formed a strong bond.