Horus

Horus Lupercal was the Primarch of the XVI Legion, the Sons of Horus, and the first among the Emperor's sons to be named Warmaster. Once the Emperor's most trusted and beloved child, Horus fell to the corruption of Chaos and led fully half of the Space Marine Legions in rebellion against the Imperium during the catastrophic civil war that bears his name. Armed with the Talon of Horus and the mace Worldbreaker, he nearly succeeded in destroying everything his father had built before being slain aboard his flagship during the Siege of Terra.