In 2012 AD, on the day of the legendary end of the world, countless demon beasts descended from beyond the heavens and landed on Earth, ushering in the greatest catastrophe in history—the Age of Great Cataclysm.
These demon beasts ran rampant across the world, while the island nation of Japan was completely reduced to a paradise for demon beasts.
Under such circumstances, humanity had no choice but to embark on a path where technology and martial arts received equal emphasis, setting foot on an unprecedented road of development.
Since the Great Cataclysm, humanity had followed this path of equal emphasis on technology and martial arts. Not only had great numbers of martial experts emerged, but technology had also made tremendous strides.
Humanity began colonizing other planets. Aside from the Moon, Mars had become humanity's second homeland after several centuries of transformation. Apart from a small portion occupied by demon beasts, most of it remained under human control.
Venus and Mercury had completely become resource planets.
Meanwhile, most regions of the more distant Jupiter had fallen entirely under the control of demon beasts. Though demon beasts lacked humanity's technology, their formidable bodies were enough to let them cross the universe. The war between the two races began spreading from Earth all the way into the depths of space.
On Jupiter, the largest planet, humanity had only a few landing Base Cities. It was fundamentally impossible to control it as they controlled Mars.
Jupiter's harsh environment posed an enormous problem for ordinary humans, but for demon beasts, it was like a fish taking to water—nothing worth mentioning.
Thus, it became the main stronghold of the demon beast race throughout the Solar System.
As the Jupiter landing Base Cities were established, Mars changed from the front line to the second line of defense.