Book 11 in Black Library’s Horus Heresy: Primarchs series, Ian St. Martin’s Angron: Slave of Nuceria explores a key moment in the early development of the World Eaters legion. Given lordship over a legion who in his eyes pale in comparison with the brothers and sisters he left behind on Nuceria, Angron demands that his sons remake themselves in his image by accepting the Butcher’s Nails. All his sons are desperate to earn his regard, but while some work tirelessly to re-engineer the Nails to be implantable into legionaries, others look to the future and fear for what will become of the legion.