With intelligence, strength, and intuitions superior to his brother's, 15-year-old Yuki Aiba has no need for his older brother Kouji, Kouji's friends or Kouji's patronizing - indeed, fights are inevitable whenever the Aiba boys meet face-to-face. A lone wolf, it is hard for him to live with others. Very athletic, and with outstanding piloting skills, Yuki ranks at the top of the Level 2 piloting class.