Futura, originally named Saki Yamamori, is a 14-year-old runaway from Kyoto whose parents opposed her dream of becoming a musical theater actress. Her past involved severe agoraphobia and social aversion, resulting in a friendless background. Initially characterized by deep reservation and pessimism, frequently voiced as her catchphrase "The future is dark," she contrasted sharply with her optimistic traveling companion. Secretive at first encounter, she wore cool shades later removed as their friendship grew. Socially withdrawn, self-described as clumsy and athletically challenged, she compensated with strong mental arithmetic skills and financial management abilities, taking charge of household expenses.

Her development stems from shared experiences pursuing entertainment careers in Tokyo. Through this journey, she gradually transitions from a shy, socially anxious individual to actively engaging in performance arts to overcome her phobias. While maintaining a pragmatic and often emotionally detached communication style—earning her the narrative role as "The Spock" to her friend's "McCoy"—she evolves from defeatism toward greater self-assurance via collaborative efforts and professional guidance.

Futura acts as the strategic foil within the partnership, contributing logical planning, industry awareness, and managing practical challenges. Her arc depicts progressive confidence-building through performance opportunities and mentorship within their talent agency, culminating in collaborative success despite initial interpersonal difficulties with established figures like Sissy.