Hayato Kobayashi, a Japanese-American civilian from Side 7, was forced to evacuate aboard the SCV-70 White Base after the Zeon attack claimed his family. Untrained for combat, Bright Noa conscripted him into the crew. He dedicated himself to simulator training and studying the RX-75 Guntank, initially serving as its gunner under pilot Ryu Jose. Following Ryu's death, Hayato modified the Guntank for solo operation, assuming both piloting and gunnery duties. This phase revealed his strong sense of responsibility, cooperative spirit, and underlying stubbornness, sometimes causing friction with command. His combat role expanded during the One Year War. He engaged in pivotal battles, sinking a Papua-class supply ship, supporting Amuro Ray in the G-Sky Easy during Odessa, and defending Jaburo where he earned promotion to corporal. After the White Base entered space, he primarily operated the Guntank, though during the Battle of Solomon he sustained injuries piloting the movie's "C-109" Guncannon. Hayato wrestled with jealousy towards Amuro Ray's burgeoning Newtype abilities and piloting prowess, feeling overshadowed. This insecurity eased as he grew closer to Fraw Bow, who shared his sense of separation from Amuro. Post-war, he married Fraw Bow. They adopted the White Base orphans Katz, Letz, and Kikka, and later welcomed their own biological child. Due to exhibiting Newtype-like abilities during the conflict, the Earth Federation assigned him to a non-combat role as a war museum director. Feeling sidelined and depressed, he joined the anti-Titans group Karaba, rising to a leadership position. In this capacity, he facilitated critical support for the AEUG, including arranging shuttle transport for their Jaburo invasion. During the Gryps War, Hayato learned of adopted son Katz's death but concealed this devastating news from his family, a burden causing profound emotional strain. Later, in the First Neo Zeon War, while most Karaba moved to space, he remained on Earth supporting AEUG operations, notably aiding Judau Ashta. Defending Judau aboard a Dodai Kai during the Dublin Colony Drop on October 30, 0088, he sacrificed himself to intercept an attack from Rakan Dahkaran's Zaku III. Before perishing in the explosion, he expressed hearing Katz's voice. He was buried near Katz in Shizuoka. An alternate narrative exists in the novel continuity, where he died protecting a shuttle from Ple Two's Psycho Gundam Mk-II, witnessed by a devastated Amuro Ray. His legacy endured. Comrades used "Hayato Kobayashi" as an alias during covert operations, like Amuro Ray's contact with Neo Zeon sympathizers in the Second Neo Zeon War. Prior to his death, Hayato wrote a letter detailing his personal life, including the incident where Kikka and the children discovered bombs in Jaburo and Amuro's role in their survival. He enclosed Kai Shiden's business card for further information, which Fraw later gave to Kikka.