The Finance King is the main antagonist of the Real Estate Royale sidestory of Yakuza 0.
The Finance King was once Yamanoi's business partner in a Tokyo real estate firm they funded together with the mission of both generating profit and improving the communities they operated in. As their success increased, however, the Finance King became increasingly greedy so he betrayed Yamanoi, drove him out of their firm and started employing any business practice possible to make all the money he could, regardless of how many people he exploited and how many laws he broke.
This new firm of his eventually led to the establishment of the Five Billionaires: a cabal of unscrupulous real estate moguls like him that, combining their properties, controlled most businesses in Kamurocho during the 1980's. The Finance King ran market manipulation, investment fraud and financial schemes to provide the other billionaires with the money they needed to expand their operations and ensure a monopoly over the areas they controlled.
After Kazuma Kiryu joined forces with Yamanoi and his assistant, Marina Shiraishi, and together they defeated the Leisure King, the Finance King started keeping an eye on Kiryu. Periodically, he would hold meetings with the remaining Billionaires every time one of their ranks fell to Kiryu's expanding business to chide them for their failures.
After the last of the other Billionaires, the Media King, was defeated, the Finance King revealed himself and sent two of his assassins to take out both Kiryu and the Media King. Regardless, both men managed to defeat the hitmen by joining forces and fighting them together.
Prior to the Media King's defeat, the Finance King had bribed Yamanoi to join his company once again and betray Kiryu by stealing the deeds to all of his properties, something Kiryu and Marina only realized after the Media King was beaten and Yamanoi vanished with the deeds.
After hearing that his assassins had failed to take out Kiryu, the Finance King sent more hitmen to attack his businesses that Yamanoi had not stolen the deeds for in order to distract him. Fortunately for Kiryu, the other members of the Five Billionaires, who'd joined forces with him after their defeats, defended his businesses from the Finance King's goons while he went to the Super Billionaire's lair to confront him.
Upon arriving to the Finance King's offices, Kiryu is attacked by another pair of hitmen, but he readily defeat them and faces off against the Finance King. Once Kiryu has arrived, Yamanoi pulls a gun on the Finance King and reveals that he only pretended to betray Kiryu so that he could find out his base's location to take him out. The Finance King pleads for his life, but Yamanoi insists that he must kill him. The murder is only stopped when Marina arrives and reveals that she was an undercover detective for the Tokyo Metropolitan Police's financial crimes division tasked with tracking down the Finance King to arrest him. While Yamanoi is distracted, the Finance King snatches his gun and tries to kill him, but Kiryu interrupts and the two have a duel, which Kiryu ends up winning.
After his defeat, the Finance King is arrested and the Five Billionaires are dissolved.
The Finance King was once an idealistic young man who believed that real estate companies could exist to both generate profit and help out their communities. As his success increased, however, he became enamored with his wealth and betrayed his previous ideals to amass the biggest fortune possible. His single goal in life is to become the world's first trillionaire and he's willing to commit any number of crimes and atrocities to achieve it.
The Finance King attacks by alternating between fast kicks and shots from his pistol. He will frequently dodged out of the way of combos to try to shoot Kiryu.
The Finance King will sometimes try to put distance between himself and Kiryu to fire his pistol with a charged shot. Before he does this, he will extend his arm and aim, like common pistol-wielding enemies. This attack is his most dangerous as it deals a substantial amount of damage.
He also employs dodge rolls where he fires while evading attacks, but these do not cause nearly as much damage as his aimed shot attack.