Demarcation Line (DL)

In 2217, the American Federation of Planets (AFP) and the Asian Capital Alliance formalized a Demarcation Line, accompanied by a strict nonaggression pact, dividing the Milky Way into two sovereign spheres of control. The DL was established using Earth’s sun as the central reference point, forming the basis of a new Galactic Coordinate System that split the galaxy along longitudinal lines.

The 0 degree coordinate extended outward from the Sun through the galactic core, cutting across the Scutum–Centaurus Arm and reaching the far tip of the Sagittarius Arm, more than 75,000 light years away. In the opposite direction, the 180 degree coordinate passed through the Perseus Arm and the Outer Arm, stretching over 30,000 light years toward the galaxy’s rim.

Together, the span from 0 to 180 degrees formed a boundary roughly 30 kiloparsecs across. Under the pact, the Capital Alliance controlled the half of the galaxy from 0° to 180°, and the Federation controlled the half from 180° back to 0°.

Between them lay the DL itself — a 100 AU wide buffer zone of restricted space. No civilian or military vessel from either side was permitted to cross it without explicit treaty authorization. A formal armistice declared Earth a war-free zone, as neither superpower was willing to risk open conflict over the homeworld. Washington, D.C. became the capital of the Federation, while Hong Kong became the capital of the Alliance, each symbolically positioned on opposite sides of the planet.

But a war free Earth did not mean a peaceful galaxy. The DL quickly became the most volatile region in known space — a narrow frontier where covert operations, territorial probes, and military standoffs were routine. The AFP was forced to reorganize its military structure to defend its territory and respond to the constant skirmishes that erupted along the line.

More than a century later, the relationship between the two superpowers remained tense, unstable, and deeply hostile. Neither side dared commit to full scale war — but neither side trusted the other. As a result, conflict in the DL remained a daily reality, a fragile boundary holding back a galaxy always on the brink.