Mutsu (陸奥, Mutsu) is the second-in-command of the merchant fleet Kaientai. In fact, she is the one running the company, instead of the usually-disappearing leader Sakamoto Tatsuma. Before then, she was the Vice-Commander of the 2nd Division of the Chidori, a group of space pirates that made money by selling slaves. However, upon learning of their plan to kill her after her father's death, Mutsu ended up being a member of the Kaientai as soon as the pirates' ships were taken over by Sakamoto.