The Zaibastu drug company gives Claude Speed missions in Grand Theft Auto 2 and provides commercials for the other Grand Theft Auto games. Doing missions for them will lower the player's faction with the Loonies, as these mental patients despise the medication that keeps them in a "calm, restful state."
The "Z's" drive the Z-Type, the second fastest gang car in the game and can be seen sporting grey suits. The Zaibatsu Corportaion is the biggest gang in GTA2, with bases on all three levels of the game. It's leaders include Trey Walsh, Red Valdez and Uno Carb.