, the Settlement Defense Front is formed as a result of a major human conflict on Earth. In the late 21st century, Earth's resources became scarce, leading to a global crisis. As nations fought over what remained, a group of radicals and extremists from various nations banded together, viewing their governments' actions as corrupt and ineffective.

This group eventually formed the Settlement Defense Front, which aimed to break away from Earth and establish its own independent colonies and settlements in space. Led by an individual named Admiral Salen Kotch, the SDF sought to create a new order and resource distribution system that prioritized their own interests.

The SDF became a formidable military force, utilizing advanced technology and a massive fleet of warships to enforce their control over the newly established settlements.