Ryusui Nanami (
Ryusui is a fairly tall, muscular, young man with shaggy blonde hair. His garb consists of a red double-breasted trench coat with a high collar, and captain's hat, designed by Yuzuriha. he has a stone marking encompassing most of his right hand, which seems to have disappeared since his second revival.
Ryusui was the Heir to the Nanami Conglomerate, and accomplished sailor. As such, he lived a wealthy and lavish lifestyle. Pre-Stone World, He has seen as greedy playboy, rarely seen without the company of beautiful women, exotic sports cars, and excessive partying. Minami was resistant to the idea of reviving him, stating that despite his expertise in ship sailing (of which he is the most skilled), his personality was akin to that of a spoiled, pampered rich boy who ordered others to do his bidding. While initial impressions of Ryusui seem to match this description, as he demanded worship and proclaimed himself the leader of the new world.
In reality, while he is arrogant and greedy, it was his greed that fueled his ambition, which was the cause of his great success pre-Stone World. He spent a great deal of time studying, and was active in ship making, from making small models, to building huge ships. The money he earned, he put toward bettering himself and the company. Senku deduced that his presence would be beneficial to the Kingdom of Science, as his greed does not only apply to himself, but to those around him. He pushes and motivates everyone.
Though a party animal and playboy, Ryusui considers all women to be beautiful. While this seems like empty praise, he even calls the elderly and children beautiful, saying that people are all beautiful in their own way. He even refuses to see a woman cry and his greed extends to ensuring they never cry again. Like Senku, Ryusui has the drive to rebuild society and make a world good for everyone to live in.
He shows that he is selfless and caring, as he was angry Suika for stowing away in their dangerous voyage. Later, as he and the crew were being petrified, he kicked Suika out of harm's way. He is quick to admit his faults, such as when he is revived the second time, Ryusui tells Suika how proud he was of her despite her heavy burden, and declares that she is a fully fledged member of the Kingdom of Science.
Ryusui was born into the Nanami Corp, a conglomerate worth 200 trillion yen they were the biggest name in Marine Shipping. from an early age Ryusui worked on model ships, ships in bottles using his 100 Million Yen allowance. By the time Ryusui reached middle school, he started captaining his own ship where he sailed around the whole world. 
When Ryusui was below the age of 13 he had his allowance reduced to 1 million yen so he used his allowance and his families reputation to invest in the Financial Markets to acquire his own wealth where was able to buy his own expensive clothes, hire his own personal trainer where he was able to win a Dodgeball Tournament. Ryusui also liked racing video games where he tried to play a Virtual Reality racing game at a Virtual Reality Center he was refused to try it due to being younger than 13. Due to that he then had a race track built for his personal use. 
Ryusui is deperified by Senku for his captaining skills. After learning money doesn't exist in the stone world, he makes his own. After learning of the poor condition of the food the villagers made, he decided to depetrify a chef. When he is told they are out of Stone Formula, he realizes Minami might have some of the formula on her. With help from Gen, he barters it from her, on the condition they make cameras for her.
After Kohaku finds oil, he and the others go to look for it.
After discovering fuel, he, Senku, Chrome and Ukyo go out on a speedboat and intercept a message from Whyman.
He, Senku, Kaseki and the rest of the Science Kingdom build the Perseus after a year.
He is repetrified by Ibara and his men. He kicks Suika of the boat before she can be petrified. He is depetrified to look for the petrified people who were tossed into the ocean. He and Soyuz first depetrify Taiju to aid in lifting Kaseki and the other petrified people.
Abilities and Skills
Master of the Sea
Years of sailing into the ocean, Ryusui develop a keen sense on how to judge the ocean. He was able to make a precise calculation and how he can pull the situation off when sailing.
He has also proven to be good at piloting an air balloon.
After spending years of sailing, Ryusui can predict the weather even when he was not on the ocean.
Ryusui is fairly intelligent. In addition to his skills with the weather, he is a skilled ship architect. He was able to deduce Minami might have Stone Formula on her since she was in charge of choosing who depetrified for Tsukasa. He was able to quickly deduce the situation, both times he was depetrified.
|Sailing Skills||5/5 A|
Ryusui has great respect for Francois' abilities.
龍 水means Dragon Water and Nanami 七 海means Seven Seas.
- He is the first person to be revived twice.
|Male||Taiju Oki • Senku Ishigami • Gen Asagiri • Chrome • Kaseki • Kinro • Ginro • Magma • Ryusui Nanami|
|Female||Yuzuriha Ogawa • Ruri • Kohaku • Suika • Nikki • Minami|
|Male||Byakuya Ishigami • Gen Asagiri • Hyoga • Senku Ishigami • Shamil Volkov • Taiju Oki • Tsukasa Shishio • Ukyo • Yakov Nikitin • Yo • Ryusui Nanami|
|Female||Connie Lee • Darya Nikitina • Homura • Lillian Weinberg • Nikki • Yuzuriha Ogawa • Minami • Mirai Shishio|