Derneuca is an enormous terrestrial world, nearly twice the size of Earth. Its environment is similar to that of Mars; arid, and a mix of craggy basalt highlands and sand-scoured deserts of iron-laced silicate dust.

Derneuca's atmosphere mainly consists of carbon dioxide and argon, but the planet's mass is great enough that measurable amounts of helium, and even molecular hydrogen, remain trapped in the atmosphere.

The planet's gravity well is deep enough that it has collected nearly a dozen small satellites, most captured asteroids. Its surfaced is scarred by many large impact craters, marking the final resting place of other captured asteroids.