Ryusui Nanami (七海 龍水 Nanami Ryūsui) is the son of the patriarch of the Nanami Conglomerate and a major player in the Kingdom of Science, along with his devoted butler Francois. He was revived by Senku for his expertise in sailing in order to captain the Perseus to the source of the Petrification. His skills at navigating by sea or air makes him indispensable as one of the Five Wise Commanders. He is also a member of the Crafting and Development Team.