Horus’s betrayal was a cataclysmic event that forever changed the fate of the Imperium of Mankind. After this tragedy, our protagonist wakes up in this world—inside the body of a Space Marine. By a twist of fate, he not only gains permission to create his own Space Marine Chapter but also discovers that his new body, once belonging to Kayvaan, comes with an incredible inheritance: control over three star systems. With his Chapter and newfound power, he must navigate the treacherous politics of the Imperium and the constant threats from xenos, Chaos, and heretics, all while carving out his legacy in this grimdark galaxy.