Tsubaki Uehara belongs to the Uehara family, sharing the surname with Anzu Uehara. She acts as the editor for Hotaru Yuyami, the protagonist, providing professional oversight for his work as a picture book author. Beyond their working relationship, Tsubaki maintains a personal bond as Hotaru's childhood friend. Her editorial duties involve confronting Hotaru's prolonged creative stagnation triggered by the death of his dog, Hanako. She actively works to overcome his grief-induced writer's block through various supportive measures. Tsubaki expresses distinct concern when Hotaru allows Kinokoinu, a mysterious mushroom-dog hybrid creature, to move into his home. Her editorial relationship with Hotaru combines encouragement with practical support throughout his professional difficulties. She functions as a stabilizing presence in Hotaru's life during his emotional turmoil.