Martian

Martian refers to anything that pertains to the planet Mars.

In Doom 3, the Martians were an ancient race of intelligent beings that were nearly destroyed by the forces of Hell. As the game progresses, the player learns that archaeological studies were conducted on Mars, leading to the discovery of this civilization. One important note is that the Martians created the Soul Cube as a means to defeat the Hellish invasion.

Most of these Ancient Martians died during the demonic invasion or were sacrificed to create the Soul Cube. The few survivors then abandoned Mars and what ultimately became of them is unknown. There are theories that they fled to Earth and that humans may in fact be their descendants.