Masaru, similar to his companions, was probably an orphan when he, along with a group of other children, was taken in by the old Tokyo government. At that time, this specific administration was leading a covert project under the supervision of Colonel Shikishima, aimed at developing psychic abilities, potentially for military and political reasons. It was here that Masaru met and formed friendships with Kiyoko, Takashi, and Akira.
The project came to an abrupt end when Akira's powers grew beyond control, causing him to ascend to a higher plane of existence. This left behind a psychic explosion that annihilated old Tokyo. The survivors of this disaster established Neo-Tokyo, while Kiyoko, Masaru, and Takashi, now known as the "Espers," were kept in extended isolation to prevent the secret project's details from becoming public knowledge. These three children were continuously administered drugs to inhibit their psychic growth to avoid reaching Akira's power levels, which resulted in premature aging and the development of physical disabilities during their youth. In Masaru's case, he developed polio and had to use a specialized wheelchair with protective glass to accommodate his inability to walk (this vehicle is also used by Kiyoko in the anime).
