A strange being calling itself "Dung Beetle" (Koemushi) becomes the children's tutor following Kokopelli's disappearance. This entity communicates verbally and is typically sarcastic. It responds to the children’s calls, including Kana who didn't sign the contract. Koemushi can teleport the children as well as outsiders to and from the cockpit, but it cannot directly teleport between two locations without passing through the cockpit first. Between battles, it converses with an unknown entity.
In the anime, it is revealed that Koemushi was originally a human from another Earth who participated in a series of battles to protect his world. He attempted to entertain their guide to become the successor, hoping to survive, but another child was chosen instead. Desperate, he pleaded for survival, leading the guide to transform him into its replacement. The person he converses with is actually his younger sister Machi, who chose to travel with him across worlds, helping gather people to sign contracts and fight for their world, similar to Zearth's group. While in the manga Koemushi's attitude towards the children is mostly sarcastic and occasionally sadistic, in the anime he becomes much more cruel, particularly when trying to convince Jun to let Kana sign the contract. When Jun refuses, Koemushi tries to force Kana to sign and ends up being shot dead by Machi using a gun given to her by Jun.
Despite clearly being bound by certain rules, Koemushi acts superior and expects others to treat him politely. He doesn’t hesitate to put others in their place if they don’t show him the respect he believes he deserves.
