Ixium, named for a minor Vle-Ya deity, was a deceptively ordinary medium-sized moon, its surface primarily formed from various unremarkable rocks and common metals. Early probes noted this and treated it as little more than a footnote; all efforts were focused on the inner moon of Clashun, which appeared at first to be a “garden world” suitable for colonization. It was only after the colony on Clashun failed (due to a hypesaline environment and spore-based local life that provoked fatal allergic reactions in humans after long-term exposure) that Ixium attracted any interest.

Squatters fleeing Clashun quickly found that the center of Ixium was honeycombed with tunnels that ranged from a few inches to hundreds of meters in diameter. The origin of the tunnels, their manner of creation, and whether there was an intelligence behind them (a subject on which the Vle-Ya were silent), remains an enduring mystery. Mathematical models have proved inconclusive, and mapping the tunnels was too gargantuan an undertaking for such a minor curiosity.

In the meantime, Ixium has become notorious as a haven for smugglers, pirates, and squatters of every stripe. Some colonists believe that the creator of the tunnels, be it a massive machine or a hive of alien creatures, resides at the moon’s core, though the heat and pressure in the deepest tunnels has made exploration beyond a certain point an impossibility.