Ryuusui Nanami is a prominent character in the anime and manga series Dr. STONE. Known for his extravagant personality and unyielding confidence, Ryuusui is the heir to a wealthy family of shipowners. He excels as a sailor and navigator, bringing essential maritime knowledge to Senku's Kingdom of Science. Ryuusui plays a pivotal role in advancing the group's technological progress, especially in navigation and resource acquisition, often driving the team forward with his ambition for adventure and boundless desire for 'greed.'