From the introduction:
Welcome to a world not too unlike our own. For some of you it may seem familiar for some reason. The fastest growing sport in this world is street fighting. While it's not exactly legal most of the countries seem content to turn a blind eye to it as it. Usually the companies sponsoring the fights have strict rules about not killing your opponent and not cheating, however there is a seedy underside to this world. A nefarious organization has wormed it's way in to the fights and seeks to take control of it. Some say that the organization is a front for warriors from another dimension trying to take over our own but bound by a pact that prevents them from outright conquering the planet instead forcing them to have their champions face this worlds champions in fair one on one combat. However that's likely just rumors. After all there are no such things as other dimension ,right? Anyways you will be spending 10 years here. During your time here you will get the chance to join fighting tournaments and compete against other warriors from around the world. Get ready, FIGHT!