He is a first-year student of Fujiyoki High School who took on a part time job at a convenience store to cope with his parents' divorce and his mother getting a boyfriend. He befriended Gauma after offering him food and was dragged into becoming one of the co-pilots of Dynazenon, the others being his classmate Yume Minami and Koyomi Yamanaka. Out of the four pilots, Yomogi's schedule prohibited him from spending more time in training for his piloting skills.