Chaos Space Marines are elite warriors in the Warhammer 40,000 universe, originally part of the Imperial Space Marines who turned against the Emperor of Mankind. They are corrupted by the powers of Chaos, gaining enhanced abilities and dark mutations, which make them formidable opponents on the battlefield. These warriors serve various Chaos Gods, such as Khorne, Nurgle, Tzeentch, and Slaanesh, each granting unique powers and traits. Chaos Space Marines often wear twisted versions of their former armor, adorned with symbols of their allegiance, and they engage in brutal warfare to spread the influence of Chaos across the galaxy.