François serves as a highly skilled butler, previously employed by the Nanami Conglomerate before the global petrification. Their full name, age, and gender are undisclosed, as primary employer Ryusui Nanami deemed such details irrelevant next to their capabilities. Petrified in 2019 while serving Ryusui at the Nanami Sailing Academy, François possesses a petite frame and ambiguously gendered appearance, characterized by sharp eyes, a serious expression, and neatly styled corkscrew curls. Star-shaped petrification scars once marked the backs of their hands, fading after revival but later symbolically recreated. François typically wears a formal butler uniform with gloves or a baker’s outfit during culinary duties. They embody calm professionalism and unwavering loyalty, prioritizing seamless service excellence by anticipating needs before they arise. François meticulously conceals fatigue, taking breaks only when unobserved, and finds deep satisfaction in fulfilling others' desires, sharing the motto "Desire is noble" with Ryusui. François demonstrates adaptability in crises, such as negotiating with adversaries to protect civilians. Key skills include culinary mastery enabling long-lasting provisions like Stollen bread and personalized beverages; fluency in Japanese, English, and French, later adding Spanish and Morse code; plus practical abilities in first aid, horticulture, childcare, observational analysis, and endurance, evidenced by walking nonstop for two days post-revival. François's story progresses through distinct phases: Revived by the Kingdom of Science to solve sea voyage food preservation, they located Ryusui and revolutionized the group's culinary capabilities, facilitating the Perseus ship's provisions and aiding operations like truffle hunting with boars. On Treasure Island, temporarily petrified during conflict, François was revived to assist repairs and sustenance, casually revealing Senku’s past marriage to Ruri. During the sea voyage to America, they managed rations, established "Bar François" for morale, provided medical aid to a wounded Senku after landfall, translated for Luna, was captured by Stanley Snyder’s forces, and later escaped. In South America, François partnered with Suika as a survival specialist for the Fort Medusa mission, protecting her during a spider-bite emergency and transmitting vital Morse code messages aiding Joel’s diamond-splitting strategy, before being petrified again. Relationships define their role: François exhibits fierce loyalty to Ryusui Nanami, defending his ambitions and acting as a parental figure during his childhood, later comforting him over relinquishing a space mission seat. They mentor and protect Suika, entrusting her with tasks like truffle hunting and serving as her guardian during covert missions. A dynamic of mutual respect exists with Senku Ishigami; François anticipates his needs, such as preparing outfits, and aids his recovery from injuries.