Seventeenth Legion of Lorgar — zealots who chose darker gods after the Emperor forbade worship. Their chaplaincy seeded heresy through the Legions.
Books
James SwallowBlood Angels
Graham McNeillHorus Heresy
Ben CounterHorus Heresy
Anthony ReynoldsTime of Ending: Chronology
Aaron Dembski-BowdenHorus Heresy
Various AuthorsHorus Heresy
Aaron Dembski-BowdenThe Horus Heresy: Chronology
Dan AbnettHorus Heresy
Dan AbnettThe Horus Heresy: Chronology
Various AuthorsHorus Heresy
Various AuthorsHorus Heresy
Various AuthorsHorus Heresy
Gav ThorpePrimarchs of Horus Heresy
Dark Imperium: Chronology
Aaron Dembski-BowdenThe Horus Heresy: Chronology
David AnnandaleThe Horus Heresy: Chronology