Kaede Saitō, a senior at Aoi Yukimura's high school, meets Aoi in a mountaineering gear store while seeking sleeping bag advice, leading to exchanged contacts and friendship. Her deep expertise in climbing and outdoor pursuits makes her the group's go-to source for technical guidance, from gear choices to trail navigation and safety. She readily recommends beginner-friendly alternatives like Mount Takao over challenging peaks such as Mount Tanigawa. This mountain focus, however, leads to academic struggles, particularly in mathematics. Within the group, she serves as a knowledgeable and supportive upperclassman.

Personally, Kaede displays a relaxed demeanor, notably standing with one hand on her hip and favoring minimal home attire like a sports bra and short tights. Her long-standing friendship with middle school classmate Yuuka Sasahara reveals a recurring dynamic: Yuuka frequently voices concern over Kaede's solo hiking safety, a reflection of Kaede's independent spirit. A specific memory involving a raincoat purchased with Yuuka underscores their deep bond and the origins of Yuuka's persistent worry.

During the second season, Kaede joins more ambitious climbs, including a Mount Fuji attempt where she remains a steady presence despite setbacks like Aoi's altitude sickness. She reflects on her personal growth from a reserved individual to a confident, passionate climber, influenced by reconnecting with Aoi and embracing group expeditions. Kaede balances her enthusiasm for challenging climbs with maintaining friendships, addressing Yuuka's concerns and integrating new members like Honoka Kurosaki. Her core identity as an outdoor specialist and mentor remains consistent throughout the series. Her interactions center on the core friend group and Yuuka.