Ryuusui comes from serious money—the Nanami Corp, a massive conglomerate worth 200 trillion yen that dominated the marine shipping industry. Growing up with a 100 million yen allowance, he spent his childhood obsessing over ships, building intricate models and ships in bottles. By middle school, he'd graduated to the real thing, captaining his own vessel and sailing around the world.
When his allowance got slashed to 1 million yen before he turned 13, Ryuusui pivoted. He leveraged what little money he had left plus his family's reputation to make moves in the financial markets, building his own wealth from there. With that cash, he could finally afford the designer clothes and personal trainer he wanted. He apparently got good enough athletically to win a dodgeball tournament.
Gaming was another passion—specifically racing sims. He got obsessed with virtual reality racing games, but hit a wall when a VR center refused to let him play because he was under 13. His solution? He just had his own race track built. Because that's an option when you're this rich.
Content compiled by AnimeList.moe from publicly available sources.