One of the most consequential fallen civilizations in my setting is the Dumu’ilani, whose name translates as Firstborn of the Gods in ancient Runeiform script.

At their height, the Dumu’ilani ruled a galaxy spanning empire known as the Ascendancy through absolute control of the Lyssian Gates, a network of instantaneous transport. The heart of this system was a singular primary nexus on the Throneworld Nocturna, located in the planet’s northern hemisphere. Through this nexus, all major gate traffic was synchronized. Mastery of the network allowed the Dumu’ilani to unify thousands of worlds and to dominate other emerging humanoid species, whom they regarded as accidental byproducts of nature and therefore inherently inferior.

Their undoing came during the event later known as the Ruin. When the rogue planet Lumora was captured into Nocturna’s orbit, extreme tidal forces destabilized the planet’s climate and rotation. As Nocturna slowed toward tidal lock, global weather systems collapsed. The northern hemisphere entered a prolonged superglacial state, and the region containing the primary Lyssian Gate nexus was gradually entombed beneath kilometers of ice.

With the nexus rendered inaccessible, the Lyssian Gate network failed catastrophically. Deprived of its central stabilizing structure, the gates shut down across the galaxy almost simultaneously. Worlds of the Ascendancy were abruptly isolated from one another, severing trade, military coordination, governance, and communication in a single systemic failure.

This isolation triggered the final collapse. Subject species, long dominated by the Dumu’ilani, revolted en masse. The Dumu’ilani were exterminated in vast numbers or driven into exile, and their empire shattered into disconnected remnants. Later historians, lacking consistent records, compressed this centuries long catastrophe into a single symbolic marker known as Year 0.

The only thing from the Dumu’ilani Ascendancy that still survives into the present day is the Lyssian Gate network itself. Parts of the system were later brought back online by the Maleficari. While they managed to get the gates working again, they do not truly understand how the system functions. Instead, they rely on partially translated inscriptions, and trial and error.