Hayato Kisaragi is the main protagonist of Hundred. He is the older brother of Karen Kisaragi originating from Yamato prior to the Second Attack, but later moved to Gudenburg due to their father's job where he befriended Emilia Hermit until his parents' death, then moved to an insitutute in Yamato. Hayato was later scouted to enroll in Little Garden with both his tuition waived and under a scholarship under the condition his little sister would receive the treatment she needed due to his high aptitude for a Hundred, as a result of him being a variant and become a first-year student in Bugeika High School.