Hikari Onozuka balances college studies with a part-time job at the Susuki cake shop alongside Aoi Yukimura. She radiates energy and enthusiasm, frequently viewing situations through a romanticized lens. This tendency manifests when Aoi seeks advice on thanking Hinata; Hikari mistakenly suggests a night climb of Mount Tsukuba, interpreting it as a perfect romantic date destination. Her speech is distinctive, marked by the verbal tic of ending sentences with "~ssu." Hikari's penchant for dramatic relationship interpretations leads to another comedic misunderstanding in the second season, where she assumes Honoka Kurosaki is Aoi's girlfriend based on Honoka's appearance and their close interactions. Primarily, Hikari provides casual advice to Aoi during their shared shifts at the cake shop.