Ryusui Nanami (
Ryusui is ironically the type of person who Tsukasa wouldn't wish to revive; someone who wants to revive the old society (social status and money). However, he can be easily tricked by Senku and Gen into cooperating. Regardless, his wisdom about adventuring at sea or air makes him indispensable as one of the Five Wise Generals of the Kingdom of Science. He is also a member of the Crafting and Development Team.
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 had a stone marking encompassing most of his right hand, which disappeared since his second revival. Ryusui soon adorned war paint in reflection of his stone markings, during Tsukasa's 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 been seen as a 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. 
Along with the rest of the world, he was petrified.
Ryusui is deperified by Senku for his captaining skills. After learning money doesn't exist in the stone world, he makes his own. Senku and Gen manage to take a good deal of money from him. 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. He uses the formula to depetrify his old butler Francois.
After Kohaku finds oil, he and the others go to look for it.
He discovers Suika stowing away on the Perseus. 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.
He is repetrified when Ibara petrifies the island. He is depetrified again when Senku tricks Ibara into hitting him with Depetrification Formula. He uses the drone to catch the Medusa.
Abilities and Skills
Master of the Sea
Years of sailing into the ocean have allowed Ryusui to 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 the Stone Formula on her since she was in charge of choosing who was depetrified for Tsukasa. He was able to quickly deduce the situation, as both times he was depetrified.
|Sailing Skills||5/5 A|
Ryusui has great respect for Francois' abilities.
As Senku needed an advanced sailor, he released Ryusui. Senku finds his skills to be incredible and was amused when he created currency, which was needed to recreate society. Ryusui also finds Senku to be more devious than him when seeing the latter work everyone around him.
Ryusui views Suika still as a kid at first, despite how much she has done for the Kingdom of Science. Nevertheless, he still cares enough about her to berate her for stowing away on their mission, as he would never endanger the life of a child. This is further seen when he kicked her off the ship to avoid letting her be petrified. After being revived a second time, he congratulates her on succeeding in her mission and declares her a true warrior of the Kingdom of Science. Since then, he doesn't look at her in the same light and trusts her enough when it comes to dangerous missions.
龍 水means Dragon Water and Nanami 七 海means Seven Seas.
- He is the first person to be revived twice.
- He is also the first person to be revived three times.
- Having been Petrified during the final battle with Ibara, he holds the record for the number of times someone has been petrified. A total of four times.
- His personality is similar to the homunculus Greed from Fullmetal Alchemist. Both are greedy individuals who have a noble side; Ryusui uses his greed to push everyone forward, while Greed values his friends.
- Juding by his personality, it seems possible that he wants to travel and explore the whole world on the Pearsus, even after they reach South America. This was later confirmed when it was revealed that they will indeed travel the world, to collect items for the space shuttle.
|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 • Ryusui Nanami • Senku Ishigami • Shamil Volkov • Taiju Oki • Tsukasa Shishio • Ukyo Saionji • Yakov Nikitin • Yo Uei|
|Female||Connie Lee • Darya Nikitina • Homura Momiji • Lillian Weinberg • Nikki Hanada • Yuzuriha Ogawa • Minami Hokutozai • Mirai Shishio|