Little is known about Machi. Her parents are fishermen, and she has described her older brother as behaving similarly to Ushiro. She was the one who discovered Kokopelli's cave but was hesitant to sign the contract until Waku pressured her into joining. When the children were introduced to their chairs, Maki initially believed Machi’s chair belonged to her.
During Chizu’s scenario, it was Machi who criticized her for the senseless killing of innocent civilians. In Kanji’s story arc, Kanji warns Jun to "watch out for Machi." Later, when he sits atop Chutenro Tower waiting to die, he contemplates who the next pilot might be but rules out Machi for reasons unknown, suggesting there is something about her that he knows but does not share with others. She later reveals that she is Dung Beetle’s Sister and wasn't part of the original contract because she came from another Earth. However, she eventually decides to sign again after Ushiro, indicating that being from another Earth wasn’t the real reason for her exclusion.
In the anime series, Kirie deduces that Machi is one of the two individuals not bound by the contract, along with Kana. Additionally, Kirie realizes that Machi knows more than she lets on, having been the one who led the other children to the cave where they made the contract and understanding the rules better than anyone else. Koemushi reveals that Machi is actually his younger sister, sent with Kokopelli to Earth to gather the rest of the pilots. Machi can also communicate telepathically with Koemushi. Tired of witnessing the same cycle of suffering and death across different worlds, Machi ultimately kills Koemushi and helps Jun protect her sister by taking Misumi’s place and becoming a pilot instead of Kana, as originally planned.
