The Emperor's Heresy: What Is the Truth?

The Emperor's sons are fiercely loyal. They united under the command of Warmaster Horus and continued to promote the Great Crusade. The victory of the Great Expedition was imminent, but a shocking news came from the rear: The Emperor, prepares to ascend to the rank of Dark Lord on Holy Terra. His sons returned to Holy Terra in shock, and a fierce offensive and defensive battle broke out. Known in history as the "Emperor's Rebellion". After the Great Rebellion, facing the fragmented empire, some Primarchs chose to maintain the Empire, some chose to self-exile, and some chose to find the truth... But... What is the truth?