Kako was a spoiled and self-centered coward with a severe inferiority complex. He acted as an errand boy for a group of bullies to avoid being their target, and his parents indulged him in almost everything, much to his older sister's dismay. Kako’s only "friend" was Kirie, who also attended the same school. Kako would constantly order Kirie around because it made him feel less like a failure, especially since Kirie never complained about this mistreatment. Kako even made Kirie accompany him to nature school for this very reason. It was here that Kako developed a strong crush on Chizu.
When he first entered the game, Kako was excited, hoping that piloting Zearth would make him famous, but upon learning the price of piloting, he suffered a mental breakdown and hid in his room. His mental state worsened when Dung Beetle visited him and told him that the other pilots were leaving him out and that his time was running short. This pushed Kako over the edge, and he went to Chizu's house with every intention of raping her, but she stopped him at knifepoint. Moments later, he and the other pilots were retrieved by the JSDF.
While being held there, Kako experienced graphic nightmares involving him beating up the bullies who used him and raping the female one, or beating his sister and Chizu while they mocked him. When the battle against Fig began, Kako hoped that the interference of the Self-Defense Force would mean he wouldn’t need to pilot and die. This hope was dashed when the futility of the JSDF's attempts became clear. Kako then panicked and started running from the battle with no intention of stopping. The group struggled to find a way to get Kako to fight, but it was Kirie who finally spoke up and made a comment implying Kako’s cowardice. This comment drove Kako into a rage, and he began to mercilessly beat Kirie. Chizu stepped forward and stopped this display by stabbing her knife into Kako’s throat and slitting his jugular. His death was unceremonious; it is the first death where no tears were shed. His chair was a straw and cloth beach chair with a wooden frame.
In the anime series, Kako did not even pilot Zearth. After he was visited by Dung Beetle, he tried to make a move on Chizu by inviting her to visit an aquarium together, but she refused. When he was selected as the next pilot, he panicked and disappeared. Chizu found him in the aquarium and tried to cheer him up, but when he tried to force himself on her, she pushed him, and he fell down some stairs, rendered unconscious. Chizu fled away from the aquarium, leaving him behind, when it was destroyed by a missile fired during the battle between the military and the enemy robot. Just after recovering his senses, Kako was killed by the debris. The children discovered what happened when his lifeless body was teleported to Zearth’s cockpit with them, and Chizu claimed responsibility for his death before being selected to replace him.
