The Gambling King is an antagonist featured in the Real Estate Royale sidestory of Yakuza 0.
The Gambling King is a member of the Five Billionaires; the cabal of unscrupulous real estate moguls that controlled most businesses in Kamurocho during the 1980's. He controlled the area around Theater Square and specialized in gambling, operating several casino halls, pachinko parlors and venues where betting could be made (such as the bowling lanes, Mach Bowl).
When he was younger, the Gambling King was a yakuza, who worked for an unspecified family. During his time in the yakuza, he founded the Japanese Catfight Club, which became so profitable it enabled him to leave his clan and strike out on his own.
The Gambling King was one of the Billionaires that Kazuma Kiryu could take on after the Leisure King was defeated.
Once Kiryu acquired 60% of the Gambling King's businesses, the Billionaire invited Kiryu to the Japanese Catfight Club, where he proposed a wager: Both of them would pick a girl for the next catfight bout and bet 10% of their holdings on the outcome. The Gambling King even gave Kiryu an advantage by letting him pick his fighter first.
Once Kiryu acquired 90% of the Gambling King's holdings, the Billionaire confronted Kiryu outside Mach Bowl and made a new bet with him: He bet that Kiryu would not survive fighting him and his goons and, if Kiryu did survive, he would get the remainder of his properties. Unfortunately for the Gambling King, he lost the bet and Kiryu would take all his businesses.
Impressed by Kiryu's luck and fighting skill, the Billionaire asked to join his company, to which Kiryu agreed. The Gambling King would become part of Kiryu's business as a manager.
The Gambling King is a rough, agressive man, who threatens others with violence whenever provoked, confident that he can take anyone on in a fight. The Gambling King is supremely confident in his luck, making bets with Kiryu even when the odds are against him.
Despite the fact that all of the Five Billionaires are unscrupulous and violent, the Gambling King is the most overt about his ruthlessness; frequently proclaiming that he will do anything it takes to win, even rigging the odds and cheating.
The Gambling King's fighting style is similar to Kiryu's "Brawler" style, fighting with middling speed but great strength. He mostly relies on punches and wide arm swings for damage and blocking for defense. However, he will also frequently dodge out of combos and get behind Kiryu to hit him in the back.
His most dangerous attack is a series of quick jabs which he often employs if Kiryu is grabbed by one of his goons. This attack stuns Kiryu and leaves him open to be crowded and attacked at once by the Gambling King and his many mooks.