Dark Heart (The Horus Heresy Short Story)

When the Word Bearers launched their surprise assault on Calth, it marked the beginning of their righteous campaign of vengeance against the hated Ultramarines Legion. But for one young acolyte of Kor Phaeron, it is not the sons of Guilliman that he seeks to bring low - through infernal pacts and daemonic power he strives to carve out a destiny for himself in the midst of the greatest war that the galaxy has ever seen. The name of Marduk shall be spoken with awe for millennia still to come... Read it because
A well-loved character from the Warhammer 40,000 Word Bearers series makes his mark in the 31st millennium, and we get new insight into what the Word Bearers were up to as they attacked Calth.