Dagonet was a world of the Imperium at the time of the Horus Heresy.
The Heresy spread to the planet, where the government swore allegiance to Horus while Imperial loyalists took to the countryside to wage a resistance movement which was led by a cult which possessed a copy of the Lectitio Divinitatus and worshiped the Emperor as a god, something outlawed in the greater Imperium.[1a] Later, Dagonet's civil war attracted the attention of the Sons of Horus, and rumors of Horus himself visiting the world emerged. This in turn attracted the attentions of the Officio Assassinorum, which employed an Execution Force led by Eristede Kell to slay the Warmaster.[1b] However the Execution Force succeeded only in killing Horus' body double, Luc Sedirae. Sedirae was a celebrated hero of the legion, and the vengeful Sons of Horus declared that Dagonet would burn for its insolence. All of its citizens and cities, traitor or loyalist, were purged in both land-based mass shootings and a fierce orbital bombardment from the Sons of Horus' fleet that laid waste to the world.[1c]