The Chaos Space Marines are traitors that, ten thousand years ago, chose to abandon their duties to humanity, betray the Immortal Emperor of Mankind and the Imperium, and instead worship the Gods of Chaos, accepting promises of power and immortality.The Space Marines are the only playable race in the single player section of the game, and the 11-mission campaign features the 3rd Company of the Blood Ravens chapter as the protagonists, led by Captain Gabriel Angelos and Librarian Isador Akios. Their troops and vehicles are more expensive, however, reflecting their limited numbers. Space Marines have the highest morale in the game. Inducted at a young age, each Space Marine receives biological modifications, a lifetime of rigorous training, and lives to experience centuries of endless battle in the defense of humanity. Space Marines are the elite, highly skilled and genetically modified superhuman soldiers of the Imperium.
Warhammer 40,000: Dawn of War features four playable armies: Main articles: Space Marines (Warhammer 40,000) Chaos Space Marines Eldar (Warhammer 40,000) and Ork (Warhammer 40,000)