Koji (, Kouji?) is one of the bandits of Mount Reikaku and is later chosen to act as their leader while Tasuki journeys with Miaka. He has known Tasuki since childhood and though he initially disliked Tasuki when he first joined the Mount Reikaku bandits, Koji and Tasuki grew close and Koji begrudgingly admitted his respect for the younger boy. Though he is two years older than Tasuki and holding more seniority amongst the bandits, Tasuki's role as a Suzaku Celestial Warrior ensured that Tasuki would be their leader.
With a completely charming way of knocking on and answering doors, Koji is the only member of the Mount Reikaku Bandits who does not dream of putting a finger on Miaka or even Nuriko or Hotohori. During the war between Kuto and Konan, Koji and his bandits offered to give assistance to Konan by agreeing to fight. After peace is restored to Konan, Tasuki returns to Mount Reikaku and resumes his position as leader from Koji, though it is generally accepted that the pair shares the responsibility.