The events of the story take place on Forge World Graia, a planet devoted to producing military weapons for the Imperium of Man which has been invaded by alien Orks. Main article: Warhammer 40,000 § Factions Portals conjured by the Traitor Legions allow daemons to enter the battlefield. The Forces of Chaos are an even greater threat, and can summon monsters that live in a parallel dimension known as The Warp. The Orks are an alien race of brutish warriors. The game's main antagonists are the Orks and the Forces of Chaos. The game also includes a new weapon not featured in the table-top game known as the Vengeance Launcher, which can shoot sticky fusion grenades. The starting weapons include a combat knife and a pistol, though the player can acquire other weapons. The game features a fury meter that, when filled up, allows the player to either slow time for aiming or perform powerful melee attacks. Titus is accompanied by the characters Sidonus and Leandros for most of the missions, though some missions are performed alone. When his health gets low, performing some actions can allow Titus to regain a portion of his health. The player character, Titus, has regenerative abilities. In Space Marine, the player engages enemies with both melee and ranged from a third-person point of view.
