The Sigillite (The Horus Heresy)

Warmaster Horus has divided the Imperium in a bloody civil war, but while his armies prepare for battle the Emperor himself remains curiously absent. In his place stands Malcador - legendary Sigillite, First Lord of Terra and regent to the throne, and now arguably the single most powerful man in the entire galaxy. Imperial Army officer Hasani Sabbyat is seconded to Malcador's command for a secret mission into the wastelands of Gyptus, and along the way he learns the truth behind the Heresy and a great deal more about the destiny of mankind. Where do Malcador's true loyalties lie?