Yakuza (ヤクザ) is a common term to refer to any number of organized crime syndicates originating in Japan. The Yakuza themselves, especially within Japan, call themselves ninkyou dantai (任侠団体, "chivalrous organization")
Like other historical crime organizations, Yakuza have made their way to the United States, where several prominent factions exist.
Japan is where the Yakuza originated. The Yakuza are who were have thought to have attacked Wiseman Hunter soon after his arrival in Japan.
The most prominent Yakuza group on the West Coast of the United States is in Seattle, Washington.
A splinter group from the Seattle Yakuza, the Tacoma group is small but formidable, nevertheless. They are lead by William, a Japanese-American who prefers to be called Godfather, rather than the traditional Oyabun.
In Chousenshi Densetsu Battle One: Revelation, William and the Tacoma Yakuza attempted to strong-arm Dino Bailey into forfeiting money to them. They were defeated by The S, Ace, C-Dogg, and Dino, with C-Dogg and Dino leading to the leader's demise.