The Marasa Nebula presented a perilous obstacle to hyperspace transit along the Trellen Trade Route, consisting of a turbulent expanse of highly charged gas. During the era of the Galactic Republic, vessels traversing this route were compelled to undertake a substantial deviation to circumvent the nebula, as passage through it was deemed unacceptably dangerous. The Galactic Empire deployed probe droids to scrutinize the area, seeking both valuable minerals and a potentially secure, shorter path. Much to the Empire's surprise, they encountered the Marasans, a sophisticated society that had evolved in seclusion within the nebula. These Marasans, having integrated navigation computers into their minds as cyborg enhancements, possessed the ability to chart routes to all thirteen systems within the nebula by identifying anchorpoints that facilitated secure passage. By the time the Empire established contact, the Marasans had expanded from their original world, Marasai, to establish more than twenty settlements throughout the nebula.
Lacking the capacity to replicate the Marasans' techniques, the Empire chose to subjugate the cyborg race, compelling them to navigate their starships through the nebula.
The Marasa Nebula also served as a habitat for giant plasma-fliers, enormous organisms that concealed themselves within the nebula's depths. Marasan spacecraft were equipped with weaponry to repel these creatures.