Miki Hoshii, a 15-year-old idol at 765 Production, navigates her career with a leisurely, carefree charm, often appearing drowsy and avoiding unnecessary effort. Her belief in effortless success stems from her upbringing under a senator father and mayor mother, who assured her a pressure-free life. Though naturally gifted—quickly mastering dances or captivating crowds with charisma—she sporadically reveals competitiveness, particularly toward her academically driven older sister, Nao.

Sporting dyed blonde hair (naturally brown), green eyes, and an athletic frame (86-55-83), Miki favors casual attire like a green beach shirt adorned with a blue butterfly paired with a jean mini-skirt. Her hobbies include crafting nail art, savoring onigiri, and indulging in strawberry Bavarian cream pastries. Before her idol debut, she frequently skipped lessons to nap at the 765 Pro office.

In *Puchimas!*, Miki bonds with Afu, a Puchidol resembling a tiny version of herself. Afu shares Miki’s love for naps and onigiri—essential for rousing her from deep sleep. During summer, Afu’s hair shortens to brown, mirroring Miki’s natural color, and sprouts a heart-shaped ahoge. Miki discovered Afu snoozing on Ritsuko Akizuki’s head post-tropical vacation, forging their bond despite early squabbles over food.

Joining idol unit Ryuuguu Komachi sparks gradual shifts in Miki’s attitude, prompting resolve to work harder without shedding her easygoing core. Her hidden talents—rapid choreography mastery and innate stage presence—clash with her reluctance to exert effort, creating a dynamic where potential flickers unpredictably. Interactions with Afu unveil her affectionate side, as she nurtures the lazy Puchidol despite their shared penchant for relaxation.