TV-Series
Description
Ryūsui Nanami is a character introduced in the later arcs of the Dr. Stone story, becoming a pivotal figure in the Kingdom of Science. He is an heir to the Nanami Financial Group, a conglomerate of immense wealth and influence with assets totaling an enormous sum. From a very young age, Ryūsui exhibited an intense obsession with sailing and all manner of vehicles, spending lavish allowances to collect models before growing dissatisfied and teaching himself shipbuilding. His passion culminated in him constructing his own vessel and successfully circumnavigating the globe while still in middle school. After humanity was petrified, he remained in a stone sleep for over three thousand years until he was revived by Senku Ishigami to assist in the search for petroleum, a vital resource for creating fuel and plastics.

Personality-wise, Ryūsui is defined by an unapologetic and all-consuming greed. He proudly proclaims himself to be the most avaricious person in the world, yet this trait is presented not as a flaw but as a powerful driving force for progress and ambition. His greed is multifaceted; it is not solely for money but for freedom, experience, and the thrill of acquiring whatever his heart desires, from a magnificent ship to a breathtaking view from the skies. This makes him exceptionally bold and decisive, unafraid to take risks or make grand entrances. Beneath his flamboyant and self-centered exterior lies a sharp intellect and a surprising sense of honor; he believes that those who work for something deserve to be compensated fairly, and his word, once given as part of a deal, is his bond.

Motivation for Ryūsui is straightforward: to satisfy his limitless desires. He is driven to explore, to own, and to experience all that the world has to offer. When Senku offers him the chance to locate a massive oil field, he agrees on the condition that he purchases the ownership rights to that oil field. This transaction allows him to establish the Ryūsui Financial Group in the new stone world, and he promptly invents and circulates the first dedicated currency, the "Ryusui Coin." For him, reviving the concept of economics and trade is a source of immense personal satisfaction and power.

Within the story, his primary role is that of a master navigator and economic strategist. His first-class navigation skills are nothing short of supernatural, allowing him to accurately perceive minute changes in temperature, humidity, wind direction, and the speed of cloud flow. This expertise is critical during the perilous journey to find petroleum, where he pilots a hot air balloon and successfully navigates through a dangerous cumulonimbus cloud. Beyond piloting, he becomes the team's financier and logistics expert, leveraging his business acumen to motivate labor and manage resources through the introduction of currency.

Key relationships often revolve around his skills and deals. His partnership with Senku Ishigami is transactional yet deeply respectful; Senku recognizes Ryūsui's greed as a predictable and powerful engine for science, while Ryūsui appreciates Senku's ability to create the wonders he wishes to own. He also has a notable relationship with Francois, the skilled butler of the Nanami household. After finding the bread he makes to be inedible, he strongly advocates for reviving Francois from petrification, knowing that only their culinary expertise can produce a loaf worthy of his refined palate.

Development for Ryūsui is less about changing who he is and more about channeling his innate traits toward the greater goal of rebuilding civilization. His greed, once focused solely on personal luxury, expands to encompass the prosperity of the entire Kingdom of Science, as their success directly fuels his ability to acquire more. He learns to leverage his desire not just for himself but as a tool to drive collective progress, becoming a key pillar of the new world's economy.

His notable abilities are extensive. He possesses a petrification release mark on his body, a scar that traces from his fingers to his wrist. His navigation expertise is his most prominent talent, allowing him to read the natural world with preternatural accuracy. He is also an expert sailor, a competent shipwright, and a natural-born businessman with a keen sense for spotting opportunities. His piloting skills, demonstrated by his control of a hot air balloon in extreme weather, further cement his status as the master of all forms of transportation in the stone world.