Akira Nishikiyama is Kiryu's sworn brother. They grew up together at the Sunflower Orphanage. He belongs to the Dojima Family alongside Kiryu, active as a hot-blooded young yakuza. He supported Kiryu at the risk of his own life to raise money for his younger sister's surgery; to him, Kiryu was more than a biological brother. He is Kiryu's irreplaceable best friend.

Kazuma Kiryu is the protagonist of the Yakuza series. With a dragon tattoo on his back, he is the legendary yakuza feared as the "Dragon of Dojima." He possesses a strong conviction to "help the weak and crush the strong," overwhelming strength, and a manliness loved by all. Raised in the Sunflower Orphanage, he met his lifelong friend Nishikiyama there. He later entered the underworld and rose to prominence in the Dojima Family of the Tojo Clan.

Reina is the proprietress of the high-end club "Serena" on Tenkaichi Street in Kamurocho, Tokyo. She has known Kiryu and Nishikiyama since they were young members of the Dojima Family, providing them with one of their few places of true relaxation.

Shintaro Kazama is the Patriarch of the Kazama Family and the foster father of Kiryu and Nishikiyama. Once feared as a legendary hitman, he is a man of deep integrity and compassion, revered by many yakuza as a "man among men."

Osamu Kashiwagi was a formidable yakuza feared in Kamurocho as the Captain of the Kazama Family and Kazama's right-hand man. Always calm and loyal, he watched over Kiryu and Nishikiyama as an older brother figure while supporting the organization.

Goro Majima is a hyper-violent yakuza feared as the "Mad Dog of Shimano," yet he lives strictly by his own sense of duty and aesthetics. Majima is extremely loyal, quick-witted, and possesses a cunning side. He calls Kiryu "Kiryu-chan" and recognizes him as a lifelong rival, while also acting as a close confidant who occasionally saves him from crisis.

Futoshi Shimano is the Patriarch of the Shimano Family. Known for his massive frame and ferocity, he is a major yakuza figure nicknamed the "Man-Eating Tiger." He is also Majima's superior and the one who triggered the birth of the "Mad Dog of Shimano."

Sohei Dojima is the Patriarch of the Dojima Family. He is the superior of Kiryu and Nishikiyama, a yakuza defined by cold-blooded cruelty and a greedy thirst for power.

Ryuji Goda is the second chairman of the Go-Ryu Clan, a direct subsidiary of the Omi Alliance. Known as the "Dragon of Kansai," he is one of Kazuma Kiryu's greatest rivals and a popular, boisterous yakuza with a strong sense of duty.

Nishida is a junior member of the Majima Family. He is a hard-working man constantly at the mercy of Goro Majima's unpredictable behavior, yet he is known as a rare voice of reason who admires his boss more than anyone else.