Koyemshi

Koyemshi (コエムシ, Koemushi) is an odd creature that becomes the children's tutor after Kokopelli's disappearance.

Character
He is able to communicate verbally, and is usually very sarcastic. He responds to the children's call, and is able to teleport them, as well as others from the outside world to the cockpit, and vice-versa. However, he cannot teleport directly between two places, and must go through the cockpit beforehand.

Manga
When Kana is chosen as the next pilot, he explains to his sister that he let Kana join the contract shortly after Kokopelli’s battle, pointing out that Kana being a pilot will actually be an advantage to this universe, since younger pilot’s presumably have stronger souls, and therefore greater control of the robots. When asked if he could teleport a plane into Zearth’s cockpit so that they could use the plane in the next battle, Koyemshi agrees to do it only if Tanaka pilots the plane, claiming that it would be more “fun” that way. This leads to Tanaka’s death, as well as Jun’s decision to join the contract and become a pilot. Along with Jun, Koyemshi’s sister Yoko attempts to join the contract, however, Koyemshi expects her attempt to be futile, since she is not from the world they are in. However, it works, and Koyemshi continues his job, supporting his sister.

When Yoko is shot, Koyemshi immediately teleports the man who shot her, and attempted to shoot Jun, somewhere else, later explaining to Sasami that he turned the assailant to ash. Yoko lives, but is in a comatose state, and Koyemshi explains that even if she regains consciousness, she will be in no state to pilot Zearth, ultimately meaning his world’s defeat. He then says that he will kill his sister, so that Jun will be the pilot for the next battle, and that Koyemshi will find the final pilot who will teach the next earth how to operate Zearth.

Reluctantly, it is agreed, and Koyemshi kills Yoko. After her death, Koyemshi shows Jun the real Yoko Machi, who is identical to his sister, and native to this world. Koyemshi goes on to explain that, although rare, there is occasionally a person in an alternate universe who might look exactly like you, as was the case with Yoko. Yoko and Koyemshi had used this to their advantage, teleporting Yoko Machi somewhere, leaving her unaware of any time that passed, and had Yoko take her place in order to lure the children into the cave and trick them into joining the contract.

When Jun asks Koyemshi who he plans on making the final pilot, Koyemshi refuses to tell, and tells Jun that he can trust him to save this universe, since his sister had wanted to save it and the people there, including Jun, who she had fallen in love with. During Jun’s final battle, which takes place on the enemy’s planet, the enemy’s Koyemshi teleports into Zearth’s cockpit, noting Jun, and then leaves. Koyemshi tells Jun that there is like some sort of trap that the enemy has planned, and to let him teleport into the enemy’s cockpit and investigate. However, Jun, not trusting Koyemshi, opens the enemy’s cockpit, revealing the pilot, who then gets teleported away. The only way for Jun to kill the enemy pilot before the forty-eight hours runs out and both worlds are destroyed, is to kill every single person on the planet until the enemy pilot is killed.

Jun spends hours killing people, eventually vomiting on himself, soiling his clothes. Koyemshi, who is surprisingly sympathetic, teleports Jun’s piloting outfit that Nakama had made, and Jun puts it on, sitting back into his chair and continuing with his task. There is a panel showing all of Zearth’s lights gone, indicating that Jun has died.

In the next chapter, titled "Koyemshi", we see Koyemshi, now human again, speaking to a new Koyemshi from Jun’s planet—presumably Sasami. Koyemshi explains what the new Koyemshi’s job is, and, when asked what his real name is, Koyemshi explains that it is not important, and tells him that the new Koyemshi will now be addressed as “Koyemshi”, and that he will now be addressed by “Kokopelli”. There are eleven people teleported into Zearth’s cockpit, Kokopelli noting that they are lucky. Kokopelli then tells the eleven pilots everything that the old Kokopelli hadn’t told the fifteen children from the last planet, including that in order to control Zearth, each of them will die, and that this is not a game. When asked if that means he will die, Kokopelli admits that he will, in fact, die after this “one-time lesson”, so that they had better pay close attention.

When the new Koyemshi asks Kokopelli if something is wrong, he replies that he would like to do something which he has always wanted to do. The chapter ends with Kokopelli saying, “Zearth, take-off.”

Anime
Koyemshi’s role in the anime is largely similar to his role in the manga, up until Kanji’s death. However, Koyemshi proves to be much more cruel in the anime, mocking and demeaning the kids openly. By the end he tries to manipulate Kana into becoming the pilot by threatening to force Ushiro into doing so if she doesn't agree; however, he ends up being shot to death by Machi, who gets tired of his machinations and works against him upon Ushiro's requests.

The anime also reveals that, back when he was a human being called Shirō Machi  he tried to amuse their guide in order to become the successor, thus being able to survive, but in the end, another child was chosen. He then begged for a chance to survive and the guide decided to accept his request by turning him into her replacement and giving him his current "Koyemshi" appearance.

Jun Ushiro
Early on, Koyemshi mocked and ridiculed Jun like he did to the others but near the end of the story they begin interacting like friends, which is what they become at the end.

Quotes

 * "There are many people who say that there's a god somewhere up there but, god is nothing more than a formula. Just a part of some law of physics that we have yet to understand." (Chapte 65: Koyemshi)