


After attacking and critically wounding a commanding officer who ordered his troops to fire on civilians, the marine was transferred to the planet Mars to perform menial guard duty for the Union Aerospace Corporation (UAC) – a megacorporation which uses Mars and its moons, Phobos and Deimos, as sites to perform military-sanctioned testing for interdimensional travel. In Doom's manual, the character is described as a marine from a futuristic earth.

Indeed, the original id Software development team deliberately avoided assigning personal identity to the character in an effort to make him an immersive stand-in for the player, leaving him nameless. The Doom Slayer was introduced as the player character in the 1993 video game Doom, in whose story text screens and instruction manual he is simply referred to as "you".
