During your investigation, you'll encounter Rikiya, a member of the Ryudo Family. He's a hot-headed but ultimately good-hearted individual who will become a key ally. The meeting will likely involve a street fight against some of his subordinates, or even Rikiya himself, as a test of strength. Treat this as another opportunity to hone your combat skills. Rikiya fights with a strong, direct style. After the fight, a cutscene will explain his motivations and he will offer his assistance. From this point, Rikiya will occasionally accompany Kiryu, providing support in certain battles. His introduction is a pivotal moment, establishing a new bond for Kiryu in Okinawa.
