Around every good hero are people to support and hinder him.
Archetypes
The Sage - Fuma Shintaro
The guide
Fuma is the catalyst for Kazuma's life as a Yakuza. Not only did Fuma kill his parents and then put him in the orphanage, it was Fuma who introduced him to the Tojo Clan and Dojima Family. Because Kazuma respected Fuma so much, I would say that FUma is the closest thing to a father that he ever had. This might also be true because Kazuma often refers to him as "pops." In fact, I assume that it ws Fuma who trained Kazuma to fight in the first place. If Kazuma needed something, Fuma was there. He was a supportive member of Kazuma's family and even gave his life for Haruka.The Sidekick - Shimabukuro Rikiya
Right hand man, support, and ear for the hero.
Rikiya appeared in Yakuza 3. When we first meet him he and Kazuma fight, but afterwards decides that he wants to be as strong as Kazuma. Despite the dragon's protests, Rikiya calls him "Aniki" (loosely means "boss" or "most honorable big brother"). He followed Kazuma around like a lost puppy. In fact, Rikiya respects Kazuma and tries his best to help him and the orphanage. If Kazuma needs something in Okinawa he can rely on Rikiya to make it happen. When Kazuma goes to find out who shot Nakahara and Daigo, Rikiya wants to tag along, but is left behind. He follows Kazuma anyways and bails him out of a tight spot. Later Rikiya gives his life because he believes in Kazuma and what he is doing.The Nemesis - Munakata Seishiro
The antagonist and those who stand in the way of the hero
It is not until Yakuza 4 that we even find out about Munakata. But he is the representation of everything that stands in Kazuma's way. After four games we finally find out that it is Munakata who has been pullign the strings behind the scenes. He was the cause for the 10 Billion Yen incident and worked closely with Jingu in Yakuza 1. He is "absent" from the games until the fourth game, but he is intertwined in every story within it, connecting even to the incident that brought the Tojo Clan to its knees. He has police men working as Yakuza to get information and Yakuza workign as policemen to keep the corruption of the focrce high. He even blackmails the sixth Tojo Clan Chairman into helping him and is responsible for arresting Majima Goro when Kazuma returns to Kamurocho in Yakuza 4.The Love Interest - Sawamura Yumi
Devoted to the hero but unable to be together
Yumi loved Kazuma and he loved her. In a perfect world, that would have been enough. When Dojima-san, Daigo's father, decides that he wants Yumi he takes her. In doing so he gets shot; as we know, Kazuma takes the fall for this. Yumi loses her memory, all but the image of Kazuma. She later has a child, Haruka, with Jingu. Fuma protects Yumi and Haruka gets placed into the Sunflowr Orphanage where Yumi visits her often. Unfortunately, Yumi goes into hiding. When she is finally reunited with Haruka and Kazuma, it is a short lived reunion as she takes a fatal bullet that was meant for Kazuma. She dies in his arms, entrusting her daughter to him.The Adoptive Family - Sunshine Orphanage
A place to call home, and usually the reason for the journeyIn Yakuza 3, Kazuma is running an orphanage. As the Unlce or sort of father to all of these children he finally has a "normal" life. He supports them, cooks for them, and makes sure that they get to school. In fact in the events of Yakuza 3, everything he does is to save the orphanage and his family. He acts as a real guardian to them giving them advice and even following them on jobs (when Haruka attempts to get one).
The Warrior - Majima Goro
Right or wrong, hell or high water, he will fight for the hero.
Despite being a battle hungry dog, Majima is a good and loyal friend. Although he starts out as an antagonist, he really becomes someone that Kazuma can rely on. In Yakuza he defends Kazuma from one of his subordinates stating that only he is allowed to kill Kazuma. He addresses Kazuma as "Kiryu-chan" and will do anything for the other man so long as he is defeated in battle. In Yakuza 2 for his assistance, Kazuma must participate in the coliseum and defeat Majima to get information. Later he fights off the entire Sengoku Family while Kazuma is busy. At the beginning of three in a flashback, Majima promises to look after the new chairman only after Kazuma has beaten him. He offers his assistance freely as a means to see Kazuma again and fight by his side. Regardless of whether or not Majima agrees with what is going on, he will help Kazuma pending Kazuma wins the mandatory battle between them. Majima shows this when he helps Tojo clan despite disliking the chairmen and despite being thrown into prison in 4.The Temptress - Sayama Kaoru
Tries to lead the hero astray
A possible love interest for Kazuma, she is a police officer. She often reminds him that she can arrest him at any time and that she will do so if he tries to run. She uses Kazuma for her own means to find her family. And often tries to steer him from his path as she constantly reminds that she is a police officer and she has no qualms about arresting or destroying Yakuza. She is hard of trusting him despite the fact that he saves her life and is doing things to try and save his daughter. She finally trusts him, finds her brother, and later leaves to train in the US. Yakuza 3 states that they are close friends, but it also stated she started seeing an American Detective.The Innocents - Sunshine Orphanage
Who the Hero fights forKazuma tries desperately to keep the orphanage safe. The plot of Yakuza 3 revolves around figuring out who shot Nakahara and Daigo while trying to keep the children safe. Most of Kazuma's time is spent looking after the children. Later, in Yakuza 4, he is even a little reluctant to get involved in incidents because he has the children to look after.
The Nightmare Creature - Yakuza Families
Creatures representive of the hero's flaws and insecuritiesThis particular representation is Kazuma's past. All the families he has fought against make his nightmare creature, or the life he doesn't want to go back too. He spends so much time trying to break free from them, but is often unsuccessful as he is pulled into wars with them constantly.
The Traitor - Nishikiyama Akira
Pretends to be for the hero but is really against them.
Kazuma's best friend, he shot the head of the Dojima family when he took Yumi. Kazuma took the fall for him and asked him to take care of Yumi. Nishiki is the reason that Kazuma went to jail. In the ten years that Kazuma is gone, Nishiki loses his sister, loses Yumi, and rises in the ranks of the Tojo clan. He orchestrates a war between families and pays Omi Alliance to help him. Kazuma finds out that Fuma's death and the third Chairman's deaths are related to Nishiki who has been trying to bring down Tojo Clan or take it over. Nishiki had feelings for Yumi, but knew that she loved Kazuma; his jealousy led him to try and kill Kazuma when the dragon was released from prison. He later redeems himself by killing Jingu and saving Kazuma and Haruka. The Dreamer - Sawamura Haruka
A reminder of why the hero fights
Kazuma's adopted daughter. He first finds her in Yakuza, in Bantam where she is holding a pistol and hiding near the bar. She refuses to follow him until he saves a puppy. It later becomes that the reason he does anything is for her. The subsequent games all revolve around saving Haruka in the midst of the Tojo clan strife. She has unending faith in him and believes that he can over come anything. When they move to Okinawa she helps to look after the other children. But it is safe to say that Haruka became his only reason for living after Yumi died. In Yakuza: Dead Souls, Haruka is kidnapped and Kazuma goes into the Zombie Quarantine to save her once again.The Fool - Date Makoto
Comic relief, also reminds the hero the journey can be accomplished and that it's for the innocents
Not always a hilarious guy, Date started out at odds with Kazuma. After the dragon was released from prison the two started to get along as they tried to unravel the mysteries of the Tojo clan war. Once a detective then a reporter turned detective again, he tries to help Kazuma but often needs saved himself. When Yumi dies and the police have Kazuma surrounded, it is Date who reminds him that he still has a reason to live. He collects information for Kazuma and often reminds him that he needs to make sure to return to Haruka. Although he cannot offer advice on being a father, he does try his best.The Rebel - Dojima Daigo
Knowledgable, skilled, huge ego. In any other story, he'd be the hero.
In the events of Yakuza 2 we see just how far Kazuma will go to keep out of the Yakuza life. Despite the fact that he doesn't want to be there, he is constantly dragged in. After Kazuma saves Daigo, he and and the chairman to be work many missions to save Kamurocho. Although it seems as though Daigo does not do as much, he is there for Kazuma and the dragon knows he can rely on Daigo. We see this when Daigo is running the family trying to disarm the bombs. We also know that Daigo tries his very best to support Kazuma even though Kazuma doesn't know it. As we see in Yakuza 3 when Nakahara tries to make him a sworn brother - Daigo officiates with a smirk though he knows that Kazuma was reluctant. In Yakuza 4, it seems as though Daigo is against Kazuma but he is really just doing what he thinks is best for the clan. Daigo holds a lot of information about the events of 3 and 4, but is unable to share them with Kazuma for whatever reason. We also see that his ego has waned over the years, but given the chance, Daigo is quite the capable leader as we get a glimpse of in the spin-off Yakuza: Dead Souls.