The ALF is a violent fanatical organisation of criminals who seek to impose their dogmatic ideology by acts of terrorism against innocent targets. Its members live in poverty and misery, crawling insides the sewers of the cities and stealing and raiding food from the marketplaces.

The UNA is an utopia first created to defend the world against forces of pure evil, and has essentially put an end to war and significantly reduced crime rates in all parts of the world. The Peacekeepers acts mainly as a law enforcement agency and use military force when necessary, such as against the ALF and other terrorist groups, such as the Sons of Schizotec.

At least that's one version of the story.