Koyuki's Keronian partner is Dororo. She found and rescued a stranded Zeroro (now Dororo) from a bear trap, brought him back to her homelike ninja village, and taught him the ways of the ninja. Under the order of the government, her ninja clan was dissolved for not having further value of existence to the country, giving her a chance(was also her only choice) at a real life in the city. Sharing many interests and the same positive attitude, Dororo and Koyuki have the most stable and cohesive relationship of the five Keronian/human child pairs. He trusts Natsumi to teach Koyuki to live a modern life.
