Heedless of warnings from nature and of social unrest, human society collapsed even as the 21st century ushered in a new era of technology. In the wake of riots, food shortages and crime, cities became ruins and were divided into armed camps. Natural disasters made life difficult for those who survived the collapse. Earthquakes and volcanoes devastated several of the earth's great metropolises. In this world of anarchy, human life was full of violence, hatred and hopelessness. The only source of amusement for these people was the Battle Game.
The Battle Game pitted two fighters against each other in arena-like combat. For the amusement of the masses, advanced technology was twisted to create giant, armored riot suits, actually hydraulically powered humanoids, called "Standing Tanks" or STs for short. Battles Between these metal monsters continued until only one combatant was left standing. Those who survived a lose in the arena became low class citizens and were forced to serve the winners.
But not all accepted their lots in life. Although his father had been defeated in the Battle Game, young Mike Anderson refused to live with the station forced on him by the Battle Game's codes. He was determined to seek vengeance on the fighter who had defeated his father: Anubis and his ST, THANATOS. Mike dedicated his life to learning all he could about the technology of the STs: their weapons, mechanical workings and defensive systems.
As Mike trained his mind and his body, however, Anubis continued to win more power in the Battle Game. Anubis promoted the best fighters in the Battle Game to be his "Chiefs." With this title each was given control over a portion of the ruined earth. Rather than issuing a standard Battle Game Challenge to another ST, Mike was faced with a more dangerous undertaking. He had to fight his way through Anubis's Chiefs to reach his ultimate goal: a battle clash to the finish with Anubis and his ST THANATOS.
--From the SNES Battle Clash instruction manual.