Eizo VI-C

Hell, or Eizo VI-C, is a frozen moon. It features in an early missions of Unreal 2, set in 2251.

Hell is one of 14 moons of the planet Gaigan, a gas giant in the Eizo Star System, about 11 times the diameter of Earth. Hell's surface is mostly rock, covered by ice spires and slush. The atmosphere consists of nitrogen, methane, and complex compounds like ethane and hydrogen-cyanide. Thermal vents release these poisonous gases into the thick, soupy sky, after which it falls back to the surface as toxic, chemical snow.

Elysium
Elysium is the only known settlement, built by the Axon Corporation as a research facility that does weapons research. The facility has a central hub surrounded with four research modules, each focused on a different area of weapons research.

Axon scientist were known to be working on a rare alien artifact, and after the TCA hasn't received transmissions from the station for 18 hours, John Dalton is sent to investigate. He finds out the facility is overrun by mutated Araknids.

Fauna
The Mukhogg is a heavily built, quadrupedal creature that can often be found sleeping on Hell's surface. Once disturbed from its sleep, an annoyed Mukhogg will attack the source until either party is killed.

The Parata is a armored, slug-like alien that lives on Hell's surface. Normally docile, the Parata will counter-attack by using some kind of glands underneath its movable sclerites.

Although they are present on Hell, inside Elysium, the Araknids, spider-like creatures, are not native to Hell. See the relevant article for info on that species.