Zombie Ultimate Fighting Champ - io is a game based on the popular universe of the same name. In this universe, a virus is injected into the blood of people, turning them into zombies. 

The virus spreads through the air, through contact with infected humans, or contact with infected meat. The game is set in the year 2036.

The game is divided into four main chapters. In the first chapter, the character meets a group of survivors, and he joins their cause. He wants to save mankind, and he is the best fighter in the group. He has a large number of friends, and he fights with a monster called "Papa Rainbow."