One of the party members you can receive in Yakuza: Like a Dragon is named Eri Kamataki. She does not immediately seem like a party member you can add to your adventure, but if you work on playing a particular mini-game enough times, she’ll happily join your party. You initially meet her as a part of the Ijincho’s Safety Net side quest, which you can start doing as you naturally progress through Chapter 5.
After you receive the side quest and start managing your business, you go through a tutorial of how the management system works and complete board meetings. At the end of the side quest, Kasuga’s old friend Nick who helped him out with his smartphone, offers the business a substantial starting amount to help get on their feet. But he has a condition: you can never be in the red, and you have to reach the top 100 businesses before a certain time period.
The primary way to increase the business’ rank is to manage the properties you own, hire new employees, and complete shareholder meetings. Successfully gaining the shareholder’s support after each meeting increases your overall rank the most. When you reach the top 100 rank, Nick will call you again and tell you of your success. He’ll also offer you another 50,000,000 to keep running the businesses. After that, Eri and Kasuga talk, and Kasuga invites her to drinks at the Survive bar.
Make your way over to the Survive bar, and you can find Eri waiting for you. Speak to her, and there will be a brief cutscene. At the end of the cutscene, Eri will announce she’s joined your party, and you can add her to the team. You can take her over to Hello Work to change her job and switch out for any of your party members to have her fight alongside Kasuga and the rest of your group.