Nagumo Tsuyoshi is the lieutenant of the Hirose Family of Onomichi. He started off as a minor antagonist and later become a supporting protagonist.
After killing their fathers to protect the Onomichi secret, Toru Hirose adopted him and Matsunaga and take care of them. At some point, he met Yuuta Utsumi and Naoto Tagashira and they form a small clan known as "Hirose Family" with Nagumo as the second-in-command. The clan worked in a protection racket in extortion for protection money from various places under the supervisions of the Masuzoe family. Nagumo also met a woman named Kiyomi and eventually had a crush on her. He became a customer in her bar and would frequently visits her.
Yakuza 6 Edit
When Kiryu arrived at Hiroshima, Kiyomi invited him into the bar. Nagumo obviously not pleased that he and the baby get all the attention while being scolded by Kiyomi for smoking near Haruto. Jealous of Kiryu, Nagumo challenges him for a fight outside the bar, and was defeated by Kiryu. Nagumo then warns Kiryu that he's the second-in-command of the Hirose family, and that he'll be back for revenge.
The day after that, he reappears with his friends, Yuuta and Matsunaga to pick a fight with Kiryu. But they're all ended up bickering among themselves and resulted in Kiryu to ignore them. Later in the baseball field, Nagumo and his friends revealed to be in the opposing baseball team. Nagumo once again feel jealous of seeing him with Kiyomi and challenges him for a match.
During the match, Nagumo purposely causing dead balls, which injures Kiryu's teammates. Kiryu then goes up for hitting. He dodges Nagumo's pitch and narrowly throws a bat at him. Nagumo then fights Kiryu again with the help of Yuuta and Matsunaga, but all three of them were defeated nonetheless.
That night, Nagumo reappears in Kiyomi's bar and once again asking Kiryu for a fight. After being defeated for the third time, Kiryu tells him to stop embarrassing himself and that he's not worth fighting. Shortly after Kiryu goes back into the bar, he was beaten up by the Masuzoe family who demands to know why Nagumo's late for bringing in the protection money. Kiyomi decided to give her money to Nagumo, but he refuses it; Telling her that if he accepts the money, he can never return to her bar as a customer anymore. This results in Masuzoe dragging him outside and beats him up some more.
Suddenly, Kiryu come to Nagumo's rescue and take down Masuzoe and his goons. Kiryu explains that he helped Nagumo because he was impressed that he stands up to his principle and stay strong in from the woman she loved. This finally changed Nagumo's perception of Kiryu and he comes to respect him as a 'brother'.
Later, Nagumo introduces Kiryu to Hirose and they both chats for a while. Suddenly, Matsunaga arrives and calls Nagumo out. He reports that he picked a fight with a customer and Yuuta said that ever since Kiryu beat them in baseball, their reputation has been decreased lately. Nagumo tells Matsunaga to take the hits instead of fight back against the customers because it's not how they handle businesses. After the rest of Hirose family left to handle with the customers, Nagumo apologizes to Kiryu for his friends' bad manners and tells him that he's welcomed here anytime.
In the next day, Kiryu tells them about his intention to find Haruto's father. He shown them the picture of Haruka, in which they suddenly get nervous.